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3D Printing Tips with Jude Pullen - Part 1: Essential Tips

3D Printing Tips with Jude Pullen: Essential Tips.

Learnings from the Good Air Canary, ESDK, and even RadioGlobe!

Jude Pullen, shares some of his best 3D printing tips, which have been the foundation of recent DesignSpark projects, such as the ESDK, Air Quality Canary, and of course the award-winning RadioGlobe. Follow this 3-part series for more pro tips...

Working with the Grain.

How to make stronger parts if you build them in the right orientation.

It might seem odd to use a ‘woodwork’ term for 3D printing, but if you are working in FDM, which prints one layer of plastic on top of another, you are in fact creating a ‘grain-like’ material structure in your print. Because of this, you can print some items like the Canary Hoop Motif, which is about 4x4mm in square profile in such a way that it is very strong and flexible for its thickness.

Similarly, if you are printing a circle, it is typically better to print these ‘flat’, as this works better than a vertical hole - where the print will have to have a ‘void’ even if print support is used, and this will give some roughness.

Of course when you have parts which have said features on both the horizontal and the vertical, then a compromise or prioritisation is needed to consider which element needs the accuracy most. Alternatively, this can be when you decide to split the feature into two parts to join later.

If you are especially interested in this, you can get into this detail from DFMA by Boothroyd and Dewhurst: (LINK), who goes into more details on the pros and cons of 1 complex part vs multiple simple parts (but that need assembly).

Nozzle to Wall Ratios.

Understand how the Nozzle Size Determines Your Wall Thickness.

Imagine if you were a Bricklayer, you would not want to have to make a wall that is 1.5 bricks wide. Rather, you would like whole numbers (integers) to be 1, 2, 3 bricks wide. At a push, you might be ok with 2.5 bricks wide as at least the cavity you can ‘fill in’ with rubble and mortar. Oddly enough 3D printers are no different.

There is a more detailed breakdown here, but in essence, you are trying to not ask the printer to print lesser thicknesses than its own size. As I mentioned in the video, these things can be a bit of a ‘trial and error’, but hopefully this will give you a tip-off as to why some walls feel stronger than others, and you’ll know to dial this in when designing parts from the start if you know your printer/nozzle-combo has ‘sweet spots’.

Print Resolution.

How to save time in prototyping by using print resolution selectively.

You of course want your final print to be as good as possible, so it’s a given this will be slow. However, you also want to print in ‘draft’ when working on the prototypes...but this risks that you might miss a critical detail? Personally, I print a high-quality print - first - of the rough shape of the final print, with all the likely features I think will be needed (even if I know the fine-tuning will change). This means that I can work in draft quality knowing it will ‘all be ok in the end’. And often if you are designing, there is no real loss in time in printing in high quality whilst you work.

Buttresses To Improve Build Accuracy.

Build your own Buttresses to avoid imperfect support material.

Build Support is a useful way for your printer to create things with ‘overhang’. However, these are made using a different composition of filament (less dense) than the usual build material. However, what you may not also know is that in-between changing from ‘Support’ to ‘Build’ material - the Extruder has to ‘retract’ the filament - and this can introduce errors into the build, as the melted filament is pressurised and depressured, and of course, the filament / gears can have some variation between such movements.

By making the buttresses as shown, you will avoid these errors, and unless you have a need to reduce a lot of weight, the pieces will likely be stronger for it anyway.

As it happens, I spoke to Alex Gibson who runs a small print bureau and he confirmed this was a good way to reduce print error, and often leads to faster and better quality prints.

In Part 2:

> Threaded Brass Inserts
> How to Remove Threaded Brass Inserts
> Shadow Gaps
> Different Part Tolerances
> When To Create Your Own Build Support...

In Part 3:

Colouring PLA
> Chamfering to Compensate for First Layer Over-Extrusion
> Happy Accidents
> Different Build Plates
> The Baby Monitor Hack

Winner of the 2020 Alastair Graham-Bryce "Imagineering" Award (IMechE), Jude thrives in high risk collaborations, uncertainty and pressure - drawing from global networks and experiences to deliver high profile campaigns and digital/physical products. A leading Creative Technologist & Physical Prototyping Expert, Jude has worked for NHS, Dyson, LEGO, and a number of start-ups. He is one of the eight featured inventors in BBC Two's Big Life Fix.
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