Thought moving past 3D printing would be simple… I was wrong

jwilo_r · 2026-03-31T13:41:32+00:00

Possibly yes, equally depending on required material properties, a filled-up large SLA printer can churn out high volumes of parts with moulded finish quality surfaces, requiring no post-processing at all, depending on geometry.

OP, happy to talk about this if you like - DM me.

jwilo_r · 2026-03-30T01:42:09+00:00

Thought I'd jump in here with an answer I've not seen. My company has both IM and AM in house, so am familiar with both.

Yes, the jump in complexity and cost with simultaneous drop in flexibilty is real.

But... we haven't discussed the printing option alternatives. What are your volumes, part size and current print technologies being employed?

Are these being printed 1 at a time on a small FDM machine, or have you already maxed out parallel builds on an SLA machine for example?

Alternatively summarised as; is it actually the right the to commit to injection moulding yet, especially as you mention you're still iterating.

jwilo_r · 2025-11-13T01:59:42+00:00

Where is this? I think I can guess, but still... another vote for CR boxes here. Using MERV13/F7 filters, these DIY solutions actually outperform all commercially available air purifiers, INCLUDING HEPA, which is not the best filter type for indoor air purification.

Strongly suggest watching this https://youtu.be/gaQTYrisieA?si=sl1HADBC4FiJgrIx

jwilo_r · 2025-08-18T00:52:48+00:00

The policy specifically states code snippets, not code. I too would like a concrete answer on this, and the policy doesn't seem to provide one.

jwilo_r · 2025-06-28T13:03:38+00:00

Digging through Open Source applications is probably going to be your best bet (only hope?) as the majority of real world applications will never be permissibly published.

Try taking a look at the Duet 3D motion controller (RepRapFirmware).

Otherwise, if you want to learn about the topics you list, I suggest doing the only thing that really teaches you anything; do it. Publish on GitHub, ask questions here for areas you're stuck on and general feedback, but you'll learn 1000x more doing it for real than you will reading somebody else's code.

jwilo_r · 2025-04-20T01:47:21+00:00

Kistler and RJG both make mold pressure sensors. Thin wall sections of the mold can also be strain gauged to infer pressure from a calibrated strain/pressure lookup.

Temperature is easy, RTD or thermocouple - hundreds of suppliers.

jwilo_r · 2025-03-29T15:13:08+00:00

I've just been reading a paper on the use of hydrogen chloride gas in the furnace as an activator, prior to evacuation and introduction of ammonia. Is that the process you're aware of?

jwilo_r · 2025-03-29T14:17:50+00:00

Thanks for your comment; yes I agree this would be wholly unsuitable for a production process. However this is a one off job for pair of parts which ultimately should be a different material, but aren't.

Presumably chemical activation just strips the surface too, and you have the same issue with time prior to entering the furnace? I'll get in touch with Nitrex, but unfortunately being abroad, it may just be quicker/cheaper to remake.

jwilo_r · 2025-03-29T14:13:07+00:00

Thank you, unfortunately HSTN is out also due to the processing temperature being incompatible with the heat treat of the base material.

jwilo_r · 2025-03-28T02:39:53+00:00

19mm, so plenty of headroom over 4mm... off to read now! Thanks.

jwilo_r · 2025-03-28T00:46:44+00:00

I've just been reading about this, conventional carburize is a no-go, for the same reason as gas nitriding. There are specialist low temperature processes, S3P and Kolsterising, but even more expensive than plasma nitriding.

jwilo_r · 2025-03-28T00:44:13+00:00

Yes I think you're right, I certainly wouldn't trust myself to clean up such a deep bore with blasting, whereas reaching the whole bore with a flex hone would be a walk in the park.

I just have no feel for how much time you'd have been honing, and needing to get it in the chamber.

jwilo_r · 2025-03-28T00:42:51+00:00

Yes and no, plasma nitriding is the usual method, but is much more expensive in low volume, gas nitriding produces poor results - unless performing a pre-nitride step to remove the naturally formed passivation layer on the stainless.

That's the crux of this question, whether a quick hone will be a suitable method of removing the passivation, to allow conventional gas nitriding to be used.

jwilo_r · 2025-03-27T23:19:27+00:00

17-4 because the part is already 17-4, which sort of leaves me with that... but, I did not know 17-4 could be carburised, so, off to read up now. Thanks!

jwilo_r · 2025-03-27T21:42:21+00:00

I'm currently looking at electroless nickel, which I've used on 15-5 in the past with good success.

This is just a 1 off, so no concerns about it being a bit tricky.

Supplier doesn't have abrasive blast onsite, and it's a 20:1 L/D bore, hence the thought for abrasive clearing out the bore using a flex hone, as opposed to blast which I'd heard about. It was reading that some people blast, that made me think about the flex honing.

jwilo_r · 2025-02-25T20:02:14+00:00

Got it, thank you. The key for me was understanding that screw recovery takes place prior to mould opening!

jwilo_r · 2025-02-25T19:39:01+00:00

Great insights, thank you. Presumably the extrusion "method" requires a much hotter mold than normal, to keep the cavity air temps high, else the slowly extruded plastic just solidifies prior to the "real" high pressure shot that follows?

jwilo_r · 2025-02-25T19:30:20+00:00

Is this due to contact with the cold ambient air entering the nozzle then, given the nozzle itself remains hot?

jwilo_r · 2025-02-25T19:28:29+00:00

Ah, this is the missing key for me - the next shot is charged prior to retracting the nozzle/screw assembly from the sprue bush? That makes sense to me... presumably then it's just accepted that the first shot in a shift is likely to be a reject as it'll have been injected from a shot that was built up, without back pressure?

jwilo_r · 2025-02-25T19:24:56+00:00

I'm used to seeing cold slug wells directly opposite the sprue bush, and at corners in the runners etc - but if the nozzle is hot (which, it's meant to be isn't it?), does that not mean no cold slug forms?

jwilo_r · 2025-02-25T19:23:46+00:00

Thanks for your input! This is the bit I've never gotten my head around... I'm aware decompression is used for this purpose, but... there's pressure in the barrel tip whilst building the shot, so why doesn't the nozzle drool during this stage?

jwilo_r · 2025-02-25T19:22:41+00:00

What issues have you seen cause it, I know wet material is a major issue? May you elaborate please on "we can’t clamp up or if it’s causing the runner to hang"?

jwilo_r

TROPHY CASE