zander engineering

Alright, time to dive into discussing the PrintNC build.

I got started on the PrintNC project after a long period of deliberation on exactly which CNC to go with, a little before the end of 2022.

It all originated from a need I identified when making soap – the need for custom soap molds. While it was easy enough to order them, they were rather expensive, and I knew that with Smooth On silicone or something similar, I could make my own and be assured they were exactly what I wanted. I didn’t want to have to place an order every time I wanted something new, be subject to die costs and minimums. I wanted that control in house.

The best way to do this was going to be to use a CNC to cut out mold masters. I had tried 3D printing, but the layer lines were unacceptable, and I couldn’t find any smoothing compounds that worked – so a CNC it was.

Initially the plan was just to get something small, but as I looked into CNCs and saw all I could do with them from a creative perspective, I decided to get something larger to make it worth my time and use it for other things as well.

I looked at a number of different options and felt that there was no perfect machine. Everyone had some compromise. You could get all of this, but it would cost that. You could get this, this, and this, but not that.

Obviously, if you paid enough you could get just about anything and everything you could want, but I had a budget to stick to, and ideally that really needed to be somewhere $3000 or less. Weighing the differing compromises between what was in my range became dizzying.

While I didn’t have control over what parts cost, I did have control over the labor and profit aspect of it. Building something myself would present a compelling way to get all or at least most of what I wanted and still stay in budget.

zNC Beta

In early 2022 I started designing a CNC and several months later finished a design for one with rotating ball nuts and double X gantries, so the Z assembly would be supported from in front and behind. Some of the parts needed for this build were beyond what my Ender 5 Pro could print in terms of size, which launched me into going through the same comparison process with 3D printers I had with CNCs, before eventually designing and building the massive cross gantry printer I’ve nearly got finished now.

That whole process of designing and building a 3D printer from scratch was eye-opening. There was a ton of work and time invested in that, and while it was worthwhile, I wasn’t sure I was ready just yet to spend that much time (or more) all over again on getting the CNC built and all the kinks worked out. I looked at a number of different ready-to-run options – Shapeoko, XCarve, Onefinity – but again they all had compromises I wasn’t happy with.

After a period of deliberation, I went with the PrintNC project. I would have to build it, so it would take some time, but it appeared to be the best overall solution between time and cost. It wasn’t perfect, but it was something to get started with at the very least.

PrintNC Kit

The PrintNC is a project you can either source entirely piece by piece yourself, or get a kit that has some of the parts all together. I went with the kit option, as it presented a pretty economically-priced bundling of all the different parts.

I ordered it ____. Probably the worst timing possible. The factories in China were going into Chinese Lunar New Year, a phenomenon unlike anything I’ve ever seen in America. Most of China basically shuts down for anywhere from a week up to a month, and there’s no official date for when any of it begins or ends, or how long it goes. That’s great for them, just something I had no real understanding of prior to this.

Communication with the factory, understandably, was very sparse. It was ordered on _____. It was shipped on or around _____ via UPS ____. The large package with all the long heavy parts in it arrived ______. The other smaller package with all the small parts sat in China at UPS for quite some time after that, and finally showed up _____. It was frustrating, but in their defense, it was horrible timing – so I’ll own that. Many others who ordered near the same time experienced the same delays.

Overall, the kit arrived in great condition. The packaging was phenomenal. I have not done a complete inventory on every last bit, but so far the only piece I’m missing is one of the collars that goes in the BK bearing block. It would probably take an act of parliament to affect such a minute change, but it would make much more sense to package those collars in the little sealed bag the ball screw end nut goes in, instead of inserting them in the BK block itself to fall out and get lost.

Sourcing the Steel

After checking with a few local places, I found a supplier that had the steel I needed that was super easy to work with. I took my machine dimensions, created a cut list, and then determined based on the lengths they sold it in – in their case it was 20’ lengths.

Before you order, I would advise checking to see what the lengths are, as some places I checked with sold it in 20 or 24’ lengths. They were able to cut things down in more manageable lengths, so I got 3x 12’ pieces and 2x 8’ pieces.

After getting it home, I measured everything out and cut it with the metal bandsaw. I’ve cut wood and aluminum before, but have never done steel. Luckily, the blade that I had was the right TPI (tooth per inch) and did a decent job cutting it.

While the recommendation is to use cutting fluid, I found over time that as it accumulated on the blade it started popping off. We cleaned all the fluid off and things improved, however it would still pop off from time to time. I would imagine the belt is probably stretched a bit, but it worked well enough to get through all the cuts I needed to do.

While cutting wasn’t that bad, drilling was an exercise in patience and a lot of frustration. In the PrintNC wiki, it’s stated that all you need is a cordless drill. I found out the hard way, likely through poor technique and possibly inferior bits, that drilling took quite a lot of work. In rather short order, I had a broken bit.

After a while of research and going back and forth on Discord, I discovered that it could’ve been a number of things:

• Too high a speed (opposite of many materials)
• Not enough pressure (opposite of many materials)
• Rocking back and forth, even a little (digs part of the bit in but not all of it)
• Starting and stopping and starting again (creates shards that the bit gets caught on)

It was amazing how long it took to get through a couple holes, even with cutting fluid, and what I thought were good bits. I got very discouraged, put everything up, and didn’t come back to it for a couple days.

Alternatives

In that interim period, I really grew to have a distaste for the steel.

The pros were that it was reasonably easy to source, affordable, and insanely rigid. The cons were that it was very heavy, not as versatile as extrusion, and much more difficult to cut, drill, and tap.

While the decision to use steel instead of aluminum was understandable – the concern of rigidity probably being at the top of the list – there wasn’t a lot of information available on the testing that had been done, which made me skeptical of the decision to seemingly throw the baby out with the bathwater.

What type of aluminum was used for testing?

Was steel chosen because it truly was the better option all around, or just because it was easy enough to get and far stiffer than an equal piece of aluminum?

I’m certain there could’ve been some rather involved analysis, but it was nowhere to be seen. Given all that aluminum had going for it, I had to get to the bottom of it.

I had this inkling feeling that there could be a solution with aluminum that would work. While aluminum is a little more difficult to source and not quite as stiff, if it meant it was far easier to work with and more versatile, I felt those could be reasonable compromises.

At any rate, the curiosity got to me. Most breakthroughs, or even improvements are discovered through AND tested by skepticism.

Analysis

I decided to run some calculations. To cut to the short, I went to ChatGPT to learn rather expeditiously what the figures were that were involved in performing analysis on rigidity. While there were programs like Fusion 360 that could do this, I wasn’t interested in learning all that; I just needed some quick answers to give me an idea on whether to continue down this road or not.

The primary concern was with the X gantry, where there’s a suspended weight – the Z axis and spindle assembly – that works on and stresses the gantry. What I was searching for was the maximum deflection I could encounter with a given weight or force. I felt as though that was one of the most important measurements of whether or not something else could work, as it’s one of the most stressed components of the machine.

Solving for Deflection

When you calculate the rigidity and the deflection of a long beam under weight, In these types of calculations on a simple long beam or piece of metal, there are a few variables:

• Modulus of Elasticity
• Moment of Inertia
• Length
• How the beam is supported (simply supported, ie just sitting on something, fixed support, attached to something, etc)

The Modulus of Elasticity is a figure that, for the purposes here, tells you what you need to know about a given material and its resistance to deformation. That’s a horrible simplification and not very textbook, but that’s what it is. The MoE is specific to a material; for any given type of aluminum, any single alloy or version, the MoE is the same, no matter what size or shape of object you have.

The Moment of Inertia is the figure that, for the purposes here, tells you what you need to know about the shape itself, the cross-sectional profile, and its characteristics as it pertains to deformation. Another horrible simplification, but finding out the differences between these two figures that one sees thrown around so often helped me a lot in understanding things.

The length takes the cross-sectional profile and creates a three-dimensional object from a two-dimensional shape. The properties of the shape (MoI), along with the properties of the material (expressed in MoE), and the length give you a unique set of variables that, when a specific type of support is determined, an equation can be used to determine the deflection.

The first formula I started with was the one that, in my case, would show me the worst possible deflection I could encounter, given a particular load. That’s the formula that describes a load of a given weight, dead in the center, with the beam supported on both sides. There are two formulas, the first for one that is simply supported, ie just resting on two supports, and the second for one that has fixed supports, ie is bolted to something that is entirely rigid.

• Simply Supported: δ = FL³∕ 48EI
• Fixed Supports: δ = FL³∕ 192EI

The variables are as follows:

• δ = maximum deflection
• F = force or load
• L = length
• E = Modulus of Elasticity
• I = Moment of Inertia

As you can see, the two formulae are pretty close to one another. One important thing is that all numbers must match in terms of units.

The length and MoI will both be measures of length or area and must match, be it inches, millimeters, centimeters, etc. The load and MoE will both be measures of weight and/or force, and also must match, be it GPa, Newtons, PSI, etc. Google can do conversions on these very easily.

To calculate all of these quite easily, I created a Numbers (or Excel, if you prefer) spreadsheet with formulae that I wrote out, that I’m happy to share here.

I created five columns: Load, Length, MoE, MoI, and Deflection. The first four columns you fill out. The last column contains the equation below. Obviously, you would replace Load, Length, MoE, and MoI with references to cells that you input those figures into.

• Simply Supported: Load * Length^3 / (48 * MoE * MoI)
• Fixed Supports: Load * Length^3 / (192 * MoE * MoI)

In the case of an X gantry, the actual figure will be somewhere between the two. While it is certainly not sitting freely on two supports, and it’s likely closer to fixed supports, there may still be some give or stretch in the system.

Results

What I found, based on data I’ve supplied for reference at the end of this post, is that the difference in maximum deflection between the 50mm x 75mm 11-gauge structural steel, and a similarly sized 80mm x 80mm section of 40 Series aluminum extrusion – both simply supported – was negligible.

In fact, based on 20lbs of weight hanging from the center, the deflection on the aluminum was 0.01mm less than the steel, a 16% improvement. It wasn’t until you went to a 50mm x 100mm 11-gauge steel profile that you saw an improvement in the steel over the aluminum, and even then it was only 0.02mm less.

You could increase the force on both and the deflection increased in a fairly linear fashion.

When you looked at all of those in a fixed support scenario, understandably, they all delivered significantly better numbers.

Going Forward

Prior to testing out these figures I’d been working on a much simplified design with aluminum extrusion. I took inspiration from the simplicity of the PrintNC, and designed an original machine built from aluminum.

My goal was to reduce the number of parts, the number of joints, the wasteful use of excess.

I took a number of the pain points, and I’ve been working to solve them to present something that is just as or even nearly as good, while being far simpler to assemble.

The question at this point was whether to order a bunch of aluminum, another $400 or so, or give the steel another go.

I decided to switch out the metric bits for some SAE / imperial bits that were much easier to get close by, and were what I felt would be a higher quality. I found out that of the 5mm and 6.5mm bits I needed, a 3/16” (4.8mm) and 1/4” (6.4mm) bit would give me nearly what I needed. I also decided to set up a rig to support the beams so I could use my drill press.

Luckily, this second attempt fared much better. The combination of the better bits and the more stable approach with the drill press proved to be a winning combo. The holes came out much better.

Unfortunately, even with the drilling working better now, there’s still a ton of holes to drill. As I’m drilling out eighty holes in five bottom crossmembers which will interface to the two side rails, which will soon have another forty holes drilled into them, and tapped mind you, the satisfaction of being able to drill better is dulled (no pun intended) by the monotony and the feeling of excessiveness in this set up.

I will pick back up on this comparison and chronicling in another post soon, to discuss a torsion box, rigidity, and more alternative ideas.

Overbuilding is common in engineering, and while it works,

The sheer weight of it, which seemed excessive, and the difficulty of working with it between cutting and drilling and tapping really turned me off.

The impression I got was it was overbuilt. While steel was definitely stiffer, I wondered if the better solution might not be a better aluminum option, than this steel one.

I did some exploratory work on aluminum. While it’s not as stiff, it is much easier to work with. But it’s just not popular, and I really wanted to understand why.

There’s a lot of talk about the inferiority of aluminum for something like this, but no real data showing numbers and evidence. While there’s been a lot of testing done, I haven’t seen evidence of a lot of engineering in a more mathematical, absolute sense. Aluminum didn’t work, so we switched to steel. I wondered, is it

I realize, looking back now, that it’s far past time to issue an update. Give me a moment to recount where I was last time.

Okay. I’m not going to go too in depth on anything. This is just to catch up.

The big printer is nearly finished.

I ordered all the parts – many more not even pictured.

After a couple failed attempts with a hacksaw, I went and bought a proper metal band saw.

I got everything cut to length, drilled, and tapped as necessary.

While these manual taps work okay, you’ll end up with a very sore hand after a short while. These combination drill / tap bits are great. I got these at Harbor Freight, and was shocked to find them in metric size. Insert the drill end slowly and straight, wait for the thread tap part to “grab hold” and it will pull itself in. Don’t push. Make sure to use a little cutting oil each time. It’s messy, but it will greatly prolong the life of your bits.

The frame is assembled.

Additional parts are printed.

Linear rails are cleaned.

All of the parts go together, motors go on.

Duet boards go in.

Belts are sized and installed.

Limit switch mounts are printed as an afterthought.

A new stand is built.

The printer makes its first moves.

The aluminum tool plate arrives. It was very poorly packaged, but the company was cool to eventually refund my shipping charges.

The silicone heat pad is added, and the new PEI spring steel build surface from Fulament arrived just the other day!

And that’s where I’ve gotten to at this point.

Next steps are to get a mount printed for the cable chain that will guide the wires for the bed heater and thermostat. I also have a few little pieces to print for various electronic parts. I have some junction strips, and I have the solid-state relay for the bed that need mounting. And then the wiring finished between them. And THEN getting the umbilical cable and all the wiring done up top. Set up the heaters in Duet web control, and then fire it up for some test runs.

Challenges

There were some design changes made. On the printer, I went against my initial decision to use 3D printed pulleys. I had no way to be certain, but I just wasn’t sure they were going to work as well as metal. I redesigned a few things and ordered metal ones.

For the longest time I had issues with belts wandering up and down the idlers. After learning more about them, I realized that due to how they are made, it’s somewhat of a normal and unavoidable thing. They were tending to bind and make bad popping and rasping noises as the carriages approached the sides. I tried a number of different alignment techniques, and eventually ended up using several bearings with a flange bearing on each end as the idlers.

Getting that fixed, and also determining that I was off by just two teeth on the front belt helped to get things in order.

Changes

The inspiration behind creating this new larger 3D printer – the aspiration to build a CNC, and the need for parts larger than what my Ender 5 Pro could print – also changed a bit.

I decided in lieu of designing something from scratch, for the time, being, to start on a PrintNC; a proven design. Working on this showed me how much work there was to creating a design from scratch. I wanted and NEEDED to get going quicker.

While it initially seemed a little overkill, I eventually warmed up to the relative simplicity of the PrintNC, and the robustness. It was ultimately going to end up being something much quicker to production.

Fairly recently I finalized my plans, ordered the kit, and went and picked up the steel the other day. The project has certainly not been without its challenges. I will share more about that in upcoming posts.

What’s Next

I’m sad to say that the Ender 5 Pro I’ve relied on for the past several years has reached its breaking point. It has been a real trooper, and is beginning to show the length of its engineering and needs some repairs to continue to function.

Given the size and capability of the new printer it may seem silly to pour money into this one, but honestly it’s been a great little printer, and does many things well – and it’s nice to have two printers in case one ever goes down or needs new parts printed. I upgraded a couple years back to the MicroSwiss direct drive kit. It included a new gantry plate, an all-metal hot end, and the necessary hardware.

It has worked well, but the hot end has always been its weak point. There’s several parts to it, and switching a nozzle often means that things get loose and then have to be tightened back up. Clogs have been a constant source of frustration, and are probably what has slowly added up leading to the demise of the extruder driver, and possibly the extruder motor as well.

As it is, XYZ functions all work, but E will run a little, make horrible grinding noises, then cease to function for several hours.

The frame of the unit is solid, so I’ve decided to upgrade it by replacing the decent but subpar Creality board with a Duet 3 Mini 5+, new OMC Stepper Online steppers (just to get a fresh start), and a new Bondtech DDX extruder with a Slice Engineering Mosquito hot end.

The order has been placed for those. Beyond waiting for those to get in, the only other thing has been waiting on parts to come in for the PrintNC.

More to come soon, on this project, the Ender 5 Pro upgrade, and the PrintNC as well.

With the design for the printer mostly finished, I’ve been going through and double checking all of what I’ve done before making the big order.

Two of the really critical parts I’ve designed are the pulleys and the cage. As you saw in yesterday’s post, the pulleys worked out quite well. After I completed those, I started printing the cage.

The cage – aptly named due to its appearance as a cubic kind of shape that holds all kinds of stuff within it – is the joint, if you will, between the extruder / hot end and the cross gantry linear rails.

The engineering that went into this required a fair deal greater precision than a lot of other parts. There were some tight clearances to negotiate around. The goal in designing it was to give it as small a footprint as possible. The reason being that any unnecessary width or depth added to the necessary length of the cross rails in order to deliver on a 400×400 XY build area.

When you design a cross gantry machine, the size of the cross rails is determined by the print volume in a given direction, plus the width of the whole hot end / extruder assembly, however much extra you need to mount the rails or rods into the side carriages, and any additional clearance space. Suffice to say, it can add up rather quickly.

Design Method

I designed it by laying out all the parts, and essentially designing the cage around the parts. I put the rails as close as I felt I could together, while still giving enough breathing room to the extruder / hot end, and ensuring that there was enough material between all these things to hold it together.

I drew out a top-down sketch, creating what I felt was adequate clearance around each part. I knew the blocks would be inside, so I created a little “wiggle” room to allow for fine adjustment, expansion / contraction and such. Did the same thing around the rails, and the hot end / extruder assembly.

I started at the bottom, and created an extruded “slice” if you will that went up to the first part interference, and then created another slice that negotiated around that part allowing for proper clearance, and then once I got above that part, the next slice returned back over that part and negotiated its way around whatever other parts it needed to.

The end result is pretty cool.

Probably the most frustrating part was the lack of attention I’d paid to support, and where it would print. There were some pieces that knocked out easy, and some that took some rather long needle nose pliers and a lot of twisting and scraping to fully remove. I will address that in a revision.

All the holes were perfectly placed. Due to the design, it is necessary to take the bearing blocks off the rails, and then reinsert the rails once the bearing blocks are installed. Last night, first time I did it, I inadvertently lose a few ball bearings. I learned the secret is to slide the bearing block into the slot in such a direction that it is upside down, and before putting the M3 screws in, gently slide the rail, wiggling it slightly until it catches just right and then very carefully continue progressing it through until it comes out the other end.

The mounts for the extruder work reasonably well. The bottom holes are flush with the extruder. I left some space on the side ones for some breathing room and a washer. I will probably take those in flush on a revision to further tighten things up. I may add an additional set of holes to match the ones up a bit higher on the Bondtech, however I really don’t care for the placement of them so close to the cleaning ports.

The whole assembly – if we’re being honest – is rather heavy. I weighed each part individually before putting it all together, and then all the parts together. It feels much heavier than it is.

But what you have to consider is that this is all being split four ways.

There are four support points on each of the XY carriages holding it all up – front, back, left, and right. That’s 455 grams a piece.

There are also four pretty decently powered motors (right now I’ve got NEMA 17s spec’d, OMC 17HS19-2004S1, with 59Ncm, or 84oz.in of holding power), each driving 25% of the entire assembly.

All of this is being driven by 10mm GT2 belt, with 30 tooth pulleys. That’s a decently wide belt, with 150-200% the tooth engagement of the size of pulleys typically used on these machines.

Contingency

At this point, I’m about ready to take the plunge and place my order.

There will be a lot of trial and error testing going forward, which has led me to consider contingency plans in the event some or all of this engineering doesn’t work out the way I need it to.

Basically, if this doesn’t work, am I going to be saddled with all kinds of parts that aren’t going to work for something else? I think that’s a universal concern, before any large investment is made. And luckily, I think we’re good in this case. All parts should translate well between different approaches.

If this cross gantry doesn’t perform up to what I need it to, the next step I think would be to switch to a slightly lighter cross gantry setup with linear rods (8mm, since I already have them) and test that out.

While the present MGN12 driven design is supremely rigid, it is also rather heavy, and who knows where the exact sweet spot is between the two, and if one is much closer than the other? Such a design change would require a new, but arguably simpler cage to be printed, along with slightly different carriage blocks to accept an 8mm rod instead of 12mm linear rails.

A rather easy modification.

If that doesn’t work, I would be open to entertaining a CoreXY setup. It would definitely take some extra work, because the sheer size of this build volume is something that CoreXY struggles with. The long gantry span, the belt lengths of over a meter, controlling ringing; there’s a lot to deal with.

But, all of these designs have so much in common with one another parts wise that I don’t see an issue with any of it.

Time to “do the thing” as they say. More later!

The breakthrough achievement I mentioned in the prior post was the successful manufacture of a 3D printed pulley.

That happened this morning.

As I mentioned in the previous post, with the CNC and more recently with the 3D printer, there’s a very specific design ethos I have with what I’m doing – partly influenced by the world I’m bringing these machines into, manufacturing things for my business, and partly influenced by the world we all live in.

That ethos is as follows:

• Easy-to-Source – something that, where off-the-shelf parts were required, those parts were as few in number and as common as possible, to avoid the inevitable dreaded manufacturing and supply chain interruptions, and to enable easy redesign / substitution when and if necessary 
• Easy-to-Build – something that, in being made up of a high percentage of user-printed parts, was designed in such a way that these parts could be printed from common, easy-to-print materials, and designed in such a way that even less-than-perfect(ly calibrated) printers could (still) yield usable parts
• Robust yet Brisk – something that (eschews the en vogue obsession with ultimate speed and lightness, something that) is strong and stable, perhaps at the expense of ultimate speed, but equipped with motors and tools with plenty of power overhead such that adequate speeds can still be reached

The beauty of this has been that not only am I able to more effectively dodge supply chain constraints, but I’m also able to create perfect custom parts – parts that allow a more cohesive and better design than having to create a machine around a bunch of off-the-shelf items.

Being able to create a part that fits in with everything else around it, instead of everything around it having to be designed to fit it – man that’s nice. Saves a whole lot of “back to the drawing board” redesign of stuff when you find out something isn’t available or won’t fit in a given area.

Pulleys and Idlers

One of the most important of parts on any CNC, 3D printer, or any similar machine are the parts involved in motion and movement. For belt-driven machines, such as the 3D printer I’ve been designing, this involves the pulleys and idlers.

Throughout the design process, I’ve spent a lot of time on Amazon, trying to design my machines around what I can get. While there are other places one can go such as AliExpress, and other 3D printing companies, no other single source has as quick of shipping or as wide a selection as Amazon.

The problem that I’ve encountered with sourcing pulleys and idlers not just from Amazon but anywhere really is tremendous inconsistencies.

Some of the listings have dimensions on them, but many do not. Of the ones that do, different ones have different dimensions. They’re all roughly the same, but one pulley will be .5mm higher or lower than another. Or one will read 12.65mm in diameter while another one is 12.75mm.

Not to mention very few of them have 8mm bore, 10mm wide pulleys. These ReliaBot 20 tooth 8mm bore 10mm wide pulleys were the only ones I could find. And unfortunately, no dimensions to know how tall they are, how high one belt will run above the other, what the clearances are. Not until I asked a question, and even then, still not all the info I needed. Anyway…

When you’re dimensioning things out and placing belt runs, running back to the product listing to double check a dimension, and then seeing one page saying “Only 17 left in stock, order soon!” and another saying “Arrives Prime by [a date somewhere between three to five weeks out]”, it’s a little unnerving. This is not good news if you have any hopes of putting together kits, sharing your plans with others, let alone building another one of these in the future.

This was something I encountered first designing the CNC, and I’ve met again with the 3D printer. It’s what inspired the first of my engineering ethos points – easy-to-source.

Printing Stuff

I decided very early on with the 3D printer to create printed pulleys and idlers instead of buying off-the-shelf. My rationale was that these are parts that are hard enough to find as it is, and could easily dry up. Doing this makes it easy to just make more of them if you need them in the future. The challenge, though, is in successfully printing them.

The resolution and accuracy of a 3D printer takes a lot of work to dial in, but it IS possible. These pulleys have very, very fine details to them, and if your printer is the least bit off, it can produce a part that looks good but just doesn’t match up well.

I’ve seen it done before though, so I figured if others have done it successfully, I can too. And luckily, that turned out to be the case.

Several months ago, I took my $400 Amazon Ender 5 Pro printer, installed a direct-drive MicroSwiss all metal hot end / extruder combo on it, did a number of tests, and improved my print quality considerably. It is possible to print really decent stuff with a cheap machine. It just takes more fiddling than some of the others, and had I not done this, I’m not sure I’d be writing this post right now.

Looking back in retrospect, I probably should’ve actually printed one of these pulleys out as a test a long time ago before designing a whole printer around them and facing a potential redesign to accept off-the-shelf parts if it didn’t work out, but there was this voice that said “just do it, you’ll figure out a way to make it work and get it all calibrated”.

Yesterday I shared some of what I’d been doing on one of the 3D printing Discord channels. I felt like there was some positive feedback to it – the printer overall. The commentary around 3D printed pulleys had some skepticism in it, specifically in my desire to manufacture instead of using off-the-shelf parts, and I understand and appreciate that.

There was some question about what would happen if the pulley fails. Truthfully, I don’t see them failing anytime soon – but time will tell. If they do, they’re super easy to replace, and I believe that printing them in PETG, ABS, Nylon, or PC could yield a very robust pulley. I’ve printed these with 100% infill, and due to the shape of them, the whole pulley is more or less a non-stop path of concentric rings of filament, which produces a rather strong part. That, coupled with the fact that there are four of them driving the XY axes (two for X, two for Y) means that they’re each pulling a half of the weight of the gantry in any given direction. Given that I’m using 10mm wide belt, and these are 30 tooth gears, means that there’s a lot of surface contact, spreading out the stress considerably.

I’m happy to report with the first print I did today, everything turned out marvelously. The pulley is designed to accept a pretty standard lock collar with a grub screw to lock onto the motor shaft and prevent rotational play. The grub screw that is in there right now and comes with them will be replaced with a slightly longer one to extend out and act as a key to maintain rotation. It is mounted on a standard 8mm hardened steel rod, which is driven by a NEMA 17 stepper motor at the bottom of the printer.

Next up – printing now actually – is the center cage, a custom part with rather tight tolerances, designed to have four MGN12H bearing blocks mounted inside, and to hold the extruder and hot end.

More soon!

It’s Saturday morning, September 24th, 2022, and I’ve decided to begin sharing a journey I’ve been on for a while now.

For some time now, I’ve wanted to write about this and share what my trials and discoveries on this journey have been, but I’ve been reluctant to, for various reasons I won’t get into at the moment.

A breakthrough achievement is ultimately what inspired me to buy www.zanderengineering.com and take the plunge. After working for a couple months now on an engineering project to design a custom-engineered 3D printer, proceeding to print one of the most critical components, and having it come out successfully exactly how it was supposed to, I decided this was more than just a hope – it was something about to undergo that metamorphosis from an idea to a real thing.

A History Lesson

Zander Engineering is the more formal and public beginning of a side of my life that’s been live for years now. I can remember as a young boy, I received a Lego set from one of my dad’s coworkers as a gift. Looking back, it seemed kind of strange, perhaps even fortuitous random event. What kind of person buys their coworker’s kid a gift? A rare one, I think. Granted, it was the 90s, and it’s a very different world we live in now.

It’s a gift that I’m very grateful for. That little car, I think it was, started an obsession with Legos. My parents and grandparents gifted me many, many more sets over those early years of my life. These gifts, I think, had quite a bit to do with what I’m writing now. They ignited the creative, imagining, designing, engineering, building gene inside me.

The sets came with instructions that showed how to take simple individual pieces and make something fantastic out of them. But the modularity of the parts also gave me the ability to take them back apart and build new things.

The original sets I got were the more aesthetically-oriented models, typically brick based, sets that had no real functional value. As time went on, I got more of the Technic sets. The Technic sets differed in that the designs yielded models that could do things. Here’s a quote from the Lego website itself:

LEGO® Technic launched in 1977 as the Expert Builder series. It was renamed Technic in 1984. The purpose of LEGO® Technic is to build advanced models using a different building style than brick-based LEGO® sets. Technic sets use specialized pieces, sometimes including motors and pneumatic elements, to create much more functionality than you can get with regular bricks. Technic pieces are very versatile and completely compatible with other LEGO® pieces, so you can often find them in other themes as well.

https://www.lego.com/en-us/service/help/technic/technic/about-lego-technic-kA009000001dckiCAA#:~:text=The%20purpose%20of%20LEGO®,can%20get%20with%20regular%20bricks.

These Technic sets helped me, to move beyond the typical visual designs to actually begin to understand different mechanical aspects. The first few sets I got had pneumatics in them, which were my first foray into models with motion. There were several subsequent models that had small motors with battery packs – very, very cool.

When the Lego Mindstorms set launched in 1998, it completely changed things for would-be engineers like myself. I remember being so excited seeing it, but so disappointed seeing the price $200, wondering how I would ever get my parents to spring for it.

Eventually, they did.

The Mindstorms set added a small computer called the RCX, which had a very basic but capable computer in it, an 8-bit Renesas H8/300 Microcontroller, with 32kb of ROM. It was powered by 6x AA batteries. It had three inputs for sensors (touch and optical) and three outputs for motors. It came with a software suite where you could use drag and drop blocks on the computer to create programs where it would run functions and use input from sensors to react to the world around it, and a nine-pin serial infrared transmitter to wirelessly download the programs to the RCX.

For that time, it was a very high-tech system, and it worked quite well.

The Effects of a Toy

All of these events were integral to my personal development. They instilled in a very young and impressionable mind this idea that, if you have an idea, and if you can find a way or read how to put the individual pieces together, you can do just about anything. It also got me interested in machines and got my brain pumping thinking about all the different things you could create a machine to do.

And in the process of designing and building these ideas I was dreaming up, it taught be about all the things that go into a good design, and the challenges that any designer faces with ensuring that their design is balanced and functional.

I learned about how to counteract the forces encountered in design, how to properly support weight, avoiding deflection in beams, countering torsion in rotational drives by ensuring the proper sizing of drive axles, different ways to secure things, and a whole host of other considerations. I developed this kind of sixth sense in engineering that gave me the ability to look at a design and rather quickly determine where the weak points were, and where failure might be about to occur, so that I could adjust.

The Application

I stopped playing with Legos as I grew older and began to inherit the responsibilities of my maturation toward adulthood. I still took them out from time to time, but I longed for some kind of system, more modern, that might give me the ability to build stronger, tougher, more capable machines.

During the height of the pandemic, I decided to revisit a high-school era hobby / business I had, making candles. The pandemic and the ensuing instability it had created in the economy and by proxy the job market meant that a lot of people were out of jobs. There were tons of people getting into candle making, and every other form of crafting, ready to start a new life for themselves and leave the companies that had left them.

While I still had a job, I had a similar desire to move on and eventually become my own boss, and to do something I really enjoyed and had some sense of direction and control over.

The problem we all were dealing with, unfortunately, were the supply chain constraints that affected the inventory of raw supplies. Vessels, the containers used for candle making were one of those, most of them being made in China and shipped over to the United States.

The idea of finding a container I liked, building a product line around it, producing say a couple thousand of these, creating a following with customers, and then having that supply dry up and having to reinvent things just didn’t sit well with me.

As I sat around in my studio, I became really frustrated with how dependent we as a country had become so dependent for the quality of life we all enjoyed on another country, really, a set of countries halfway across the world.

This was a weakness of the grandest proportions, one that I was intent to find a way around.

I decided that my mission going forward (something that is one of the integral core values of Zander Engineering) was going to be to subvert the supply chain constraints by becoming my own supplier, to as great a degree as possible. The goal, in whatever I did, was to minimize the number of things I had to order, and to make whatever I had to order as common and readily available as possible.

I looked into different options. Aluminum and glass were the most common vessel materials. Making my own glass containers would require a tremendous investment in equipment, and a lot of space to produce it, as would aluminum. Though it was not as popular, I noted some manufacturers used concrete. Concrete, while kind of heavy, was everywhere, had low production costs, and was easily formed into molds. It was perfect, at the very least for getting this company off the ground until I had the means to produce my own glass and aluminum vessels.

I did a little research, looked into what would be necessary to create some molds, saw the need to create a “master mold” to cast some silicone molds from, and I ended up purchasing a 3D printer off Amazon to 3D print that master mold. I’d heard a little about 3D printing before, but had only really seen it used for little action figures and trivial esoteric goods. I suppose I knew it had also been used for manufacturing functional parts, but that had never been something on my radar, so I’d never paid much attention to it.

A Whole New World

Getting a 3D printer, learning CAD, and how to create things was like getting my first Lego set all over again.

It was, in effect, that new more capable means for making things that I’d been longing for to quench that creative itch I got from time to time. I spent some time working on the molds, which then got the wheels turning to look into creating soap. I created several test runs, and then decided I’d like to create my own custom soap molds.

While the 3d printed mold masters worked okay, I encountered issues with horizontal banding showing up in the molds. When a 3d printer prints a part, it’s basically taking a three-dimensional shape, and drawing it out with molten plastic filament, one layer at a time, creating honey-comb like structures inside of it to give it strength and rigidity. In doing that, it creates lines. I didn’t like that.

I did some more research and found that the preferred way to make these silicone molds was actually to carve the mold masters out of a dense material – usually a modeling foam, something like the pink sheets of foam insulation used in homes. This was commonly done with a CNC router.

As I looked into CNC routers and discovered all that you could do with them, I saw yet another new product stream for my company – carved and engineered wood products. As I learned about fourth-axis CNCs, I saw all that could be done to create amazing goods. I decided that if I was going to get a CNC, I was going to not just get a simple one, but a very capable one.

The problem was the cost. They were all rather expensive, the good ones anyway. And the class-leading ones that were borderline affordable all were designed with parts and in ways that made the engineer inside me question whether the bang for the buck was really there. I looked into the possibility of building my own CNC, to see if I could save some money and come out with a better product.

There were several different DIY CNCs, but they all had their tradeoffs and pain points that users dealt with. I decided, with what I knew, that I could analyze and critique these designs, and come up with something better; more suited to my needs. Something that would stand up to the test of time and high duty cycles that I knew, if I was to use these to start producing products to sell, they would encounter.

Zander Engineering

That’s about the moment that the idea for Zander Engineering actually really began to take off. That was in _____.

Over the next few months, I went through a number of different design iterations, before finally reaching a point where I was happy enough to build a BOM (bill of materials, a list of everything you need to order to build something) and start ordering.

The objective that I had were:

• Easy-to-Source – something that, where off-the-shelf parts were required, those parts were as few in number and as common as possible, to avoid the inevitable dreaded manufacturing and supply chain interruptions, and to enable easy redesign / substitution when and if necessary
• Easy-to-Build – something that, in being made up of a high percentage of user-printed parts, was designed in such a way that these parts could be printed from common, easy-to-print materials, and designed in such a way that even less-than-perfect(ly calibrated) printers could (still) yield usable parts
• Robust yet Brisk – something that (eschews the en vogue obsession with ultimate speed and lightness, something that) is strong and stable, perhaps at the expense of ultimate speed, but equipped with motors and tools with plenty of power overhead such that adequate speeds can still be reached.

((The beauty of this design approach is in what it means for my ability to create completely custom parts that might not otherwise be available to create a better design.))

The problem that I encountered was that several panels I had designed, that I intended to have cut from aluminum and custom machined to act as integral frame portions, ended up coming out to be completely cost-prohibitive. Though my machine was much more stable and robust than the machines I could’ve easily bought, it was also set to be about twice the cost if I went this way.

As I looked at my options, I saw that while aluminum was expensive, it was the machining that really cost so much. What I was needing to do in terms of machining was rather simple, so after a little research I went on Amazon and bought a small desktop CNC capable of doing aluminum.

Unfortunately this machine was a disaster.

While it was built well, the whole control aspect of it – the process of creating a model, loading it, and running the GCODE (a type of file with instructions used to tell a machine what to do) – was damned near impossible. Being a Mac user made it even worse, as all the programs ran on Windows, and as such, not very well.

After looking into the viability of 3D printing these parts instead and determining that it should meet the needs of the project adequately, I decided to return the unit and go a different direction.

The Final Straw

The problem that I encountered (are you beginning to see a pattern?) was that unfortunately the Ender 5 Pro 3d printer I had was just a bit too small to handle the size of these pieces. I researched what it would cost to have someone else print these for me, and given that, and the fact that much of the rest of the CNC machine was to be put together with 3D printed parts, I decided to get a new, more capable 3D printer.

As I looked at my options, there were many, but it was the same story as with the CNC. There were options, but they were all rather expensive, as they had the essential CODB (cost of doing business) that supports the company, the engineers, and provides user support built into them. I looked at a number of different open source options, but I didn’t care for them as they didn’t really fit the criteria I had for the printer, nor the engineering ethos that I’d developed.

I set out in _____ with a short list of objects to design, just as I’d just finished doing with the CNC project, a suitable 3D printer. Like the CNC, it was to be easily-sourced, easily-built, and robust.

Yesterday, I reached the completion point of the working draft.

There are a few small things left to put together, but on the whole, it is a complete design with no large variables left out in the open.

That closes this post up, and now, hopefully we’re all caught up to speed, and I will continue on with regular posts detailing what goes on from here.

Thanks for reading!