Another thing I do in my spare time...
How about I write something that's not cybersecurity-related? Would that be OK?
A friend messaged me last night saying he needed a "nest" made in order to complete machining on a component for his scale model of a live steam traction engine (See? told you it wasn't about security...).
When I'm not parked in front of a pile of tech, I spend my time in my Man Cave which is filled with a wide arrangement of mechanical goodies - a manual lathe, manual milling machine, welders, presses and an ever-growing array of engineers tools.
In my "other lab" (not my cybersec lab), I have my electronics workbench and 3D printer.
My friend Chris needed a simple component 3D printed so he could use it to hold (nest) some brass fittings in his lathe while he performed the final machining.
If this was a commercial workshop, you wouldn't bother with 3D printing this kind of fitting - you would grab a chunk of plastic or aluminium, whiz it up in a lathe in under 15mins, and get on with it, but I've never printed fittings for this use, so it was a chance to do an experiment.
Roll on Saturday morning, and after a bowl of cereal, I jump on my PC, open Autodesk Fusion360 - a tool for designing and producing all manner of wonderful devices. From 3D prints, to mechanical parts, to full motion assemblies and design of printed circuit boards - Fusion has you covered - and for home users, a free licence is available. I run a paid version because of the complexity of some of the shenanigans I get up to, such as this model of a New Zealand Railways AB class steam locomotive. Currently, I've drawn around 300 components on this model (not all visible here). "Why?" you ask? Well, I have a full casting set for a live steam model of this loco at about 1/8th scale, so that's another project that is begging for my attention. This will likely take me 10 years of spare time to build.
I design Chris' simple part... (under 10mins).
Yup - super-simple - 40mm OD, 26mm ID, length of 35mm.
There is nothing complicated about a short tube.
In Fusion, this is as simple as drawing the profile, extruding it to the desired length and exporting to the 3D printer slicing tool of your choice.
Once exported to my slicer (Cura), the model is broken down into layers that print at the resolution of the printer. My printer is a mid-range home model, a Sovol SV-01, which I've had for about 3 years. 3D printing in itself is almost a dark art form as there are a number of tips and tweaks you can only learn by experience (and the help of a lot of Googling and online forums).
I brought my first printer about 6 years ago, a cheap kit set printer that is renowned for catching fire and being horribly unreliable (I didn't know either of those things at the time I brought it though). The downside of such a nasty device is that the output is equally as nasty. The upside is, you learn everything about how 3D printing works and you learn how to solve a lot of problems. Thankfully, mine never caught fire.
Once the slicer has done its magic, you can preview your model. The image shown here is a sectional view of about 1/2 the length of Chris' nest. Each layer of the model is 0.1mm thick, so for this 35mm model, there are 350 layers to print. The green circles are the walls, in this case, 3mm thick. The cyan brim at the bottom of the model helps it stick to the print bed during the print. You can see the infill pattern in orange. In this case, I used 30% infill to give the model a good amount of structural strength as it is going to be gripped in a lathe chuck.
Onto the printer, it goes.
Once the printer has heated, you have to level the print bed to ensure that the model adheres well, and has a level base.
The print filament is Polylactic Acid (PLA) which is the most commonly used filament for hobby use. PLA can be used to create patterns for casting and we have made a number of widgets for around the house and cars. PLA becomes flexible around 60degC, and flows through the print nozzle at around 190DegC - don't touch the print head while it's hot.
Although this is a small print, home 3D printing is not a quick task. This print will take 5 hours to complete. Again, this is overkill for such a simple component, however, if you needed to test a new design before going to the expense of manufacturing it, 3D printing is very cost-effective. While this model prints, I make a dump run, write this article and get into the cave to work on my own projects. A couple of hours later, I check on the print and it's 40% complete. On track, looking good, no problems here.
The ability to "load, level and leave" a 3D printer is fantastic. Some of the patterns for my other locomotive project (yes, I have 2 on the go) take well over 24hrs to print. Take this wheel for example. Again, designed in Fusion360, this is a 36hr print and we're onto about revision 4 as I notice errors, or decide that something will look better if done another way.
Once I'm happy with the design, this pattern, and its friends will go off to the foundry to be cast in medium tensile steel before being machined and fitted to the locomotive. There are 6 of these large wheels, which use two different designs.
3D printing and machining in my cave are a welcome break from the world of my career, and who knows, there may be a time when I can do this as a revenue-earning exercise, but I think that would take away a lot of the enjoyment I get from just tinkering.
We won't know if Chris' nest is successful until he collects the finished print and tries it in his lathe. I think it will work. 3D printing can be madly accurate if you take the time to tune the printer - I haven't gone that far as I don't need sub-millimetre accuracy, so Chris might have to sand a bit here and there, or turn shaving off the internal diameter to fit his part. There is a chance that it won't work at all, but that's all part of the experimentation process, and you learn a lot while you do it.