RepRap/injection molding question I wanted to ask the community about a thought I had for an injection molding idea. I have ther need to create a small part , a box that is 30mmx20mmx20mm (hollow) 2mm walls (@ 3 grams of ABS), and want to do it injection style for strenghth and looks, not to mention speed. so I wondered if I could convert or use a reprap style extruder/hotend to do the job. I'm not opposed to building a small injection machine, but the whole machine seems like it would be a bit much for what I want to produce, and it would take some time to re-coop the money spent building it. My biggest concern is feeding fast enough and having enough pressure to fill the mold. the idea was to create a hotend with an orifice large enough to flow quickly. Perhaps rotate the heat cartridge to it is parallel with the hotend giving a longer hot zone. and a wades style exturder. I have also thought about feeding 2 filament into one hotend to increase flowrate. Before I begin a project, that in my head works, I thought I would ask if I am way off the mark in my thoughts. I have no experence with with injection molding, but have been researching the topic. it seems pretty straight forward, but again, so do so many other things I have failed at. If someone could point out the flaws with my idea. I'm sure I am missing something - my guess is the amout of force it takes to fill the mold in a timely manner. Thanks https://reprap.org/forum/read.php?1,390313,390313#msg-390313 Sun, 12 Apr 2026 12:47:07 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?1,390313,391294#msg-391294 Re: RepRap/injection molding question https://reprap.org/forum/read.php?1,390313,391294#msg-391294
So give it a try, and see how far you get.]]> A2 General Tue, 05 Aug 2014 17:32:43 -0400 https://reprap.org/forum/read.php?1,390313,390878#msg-390878 Re: RepRap/injection molding question https://reprap.org/forum/read.php?1,390313,390878#msg-390878
Quote
cat.farmer
[...] hope my wife [...]

Try to make some ornaments or similar and she might even help you :-)]]> Traumflug General Mon, 04 Aug 2014 04:37:29 -0400 https://reprap.org/forum/read.php?1,390313,390571#msg-390571 Re: RepRap/injection molding question https://reprap.org/forum/read.php?1,390313,390571#msg-390571
Quote
gmh39
You can print it at your highest resolution and solid infill then put it in an acetone vapor bath.
I did think about that, but I need a clean, professional looking product. I don't think the vapor bath would give me the finish I am looking for.

A2 I swear you live in a reseach facility, you always have great and detailed answers.

Traumflug - you have given me hope.

I have thought about heating the mold to help off set the quick cooling and get a full fill.

I'm going to give it a try, If it doesn't work, we'll put that on the failure pile and hope my wife doesn't see the receipts.]]> cat.farmer General Sun, 03 Aug 2014 08:24:53 -0400 https://reprap.org/forum/read.php?1,390313,390536#msg-390536 Re: RepRap/injection molding question https://reprap.org/forum/read.php?1,390313,390536#msg-390536 Traumflug General Sun, 03 Aug 2014 05:11:46 -0400 https://reprap.org/forum/read.php?1,390313,390471#msg-390471 Re: RepRap/injection molding question https://reprap.org/forum/read.php?1,390313,390471#msg-390471 [www.youtube.com]

Look for a resin that has a low viscosity, i.e. flows like water, less your object requirements dictate otherwise.]]> A2 General Sat, 02 Aug 2014 18:44:58 -0400 https://reprap.org/forum/read.php?1,390313,390382#msg-390382 Re: RepRap/injection molding question https://reprap.org/forum/read.php?1,390313,390382#msg-390382
The acetone should "melt" the layers together enough to get closer (or all least closer) to injection molding strength.

That's about as close as you can get for larger parts. There is an instrustable with a guy that uses his makerbot to injection mold but it. Was with small parts.]]> gmh39 General Sat, 02 Aug 2014 13:23:02 -0400 https://reprap.org/forum/read.php?1,390313,390316#msg-390316 Re: RepRap/injection molding question https://reprap.org/forum/read.php?1,390313,390316#msg-390316 Take a look at some videos of the hand toggle operated injection molds, you will see that quite a bit of force is being exerted to push the plastic in.

But I like to see people try, you never know, you could come up with an easy hack to make it work, but simply placing the nozzle of a typical hot end into a mold and expecting it to fill, I don't see it happening.]]> A2 General Sat, 02 Aug 2014 09:39:48 -0400 https://reprap.org/forum/read.php?1,390313,390313#msg-390313 RepRap/injection molding question https://reprap.org/forum/read.php?1,390313,390313#msg-390313
I have ther need to create a small part , a box that is 30mmx20mmx20mm (hollow) 2mm walls (@ 3 grams of ABS), and want to do it injection style for strenghth and looks, not to mention speed.
so I wondered if I could convert or use a reprap style extruder/hotend to do the job. I'm not opposed to building a small injection machine, but the whole machine seems like it would be a bit much for what I want to produce, and it would take some time to re-coop the money spent building it.

My biggest concern is feeding fast enough and having enough pressure to fill the mold.
the idea was to create a hotend with an orifice large enough to flow quickly. Perhaps rotate the heat cartridge to it is parallel with the hotend giving a longer hot zone. and a wades style exturder.

I have also thought about feeding 2 filament into one hotend to increase flowrate.
Before I begin a project, that in my head works, I thought I would ask if I am way off the mark in my thoughts. I have no experence with with injection molding, but have been researching the topic. it seems pretty straight forward, but again, so do so many other things I have failed at.

If someone could point out the flaws with my idea. I'm sure I am missing something - my guess is the amout of force it takes to fill the mold in a timely manner.

Thanks]]> cat.farmer General Sat, 02 Aug 2014 09:23:20 -0400