Using SLA 3D printers for prototyping cases - Page 1
Forum section: electronics / general

author: Korken
author_rank: Regular Contributor
timestamp: August 02, 2016, 05:20:42 pm
content: Hi all,I have been designing cases for some hobby products and the shapes are currently becoming problematic for my FDM printer (both quality and to even succeed).So I have started looking at SLA printers, such as the new Formlabs one, and wonder if anyone here has tested them for general case prototyping?Perhaps someone here has one and can give input on how the experience was? Or if someone has a link to someone with a blog in the area?Thanks in advance!

author: MicroBlocks
author_rank: Contributor
timestamp: August 02, 2016, 05:46:37 pm
content: If supports or planes on difficult angles are your problem try cutting up the model into 2-3 pieces and rotate those to minimize support and other difficulties.Most problems can be solved by this. And then you just glue them together.Often it prints faster as less support is necessary and the quality higher because you place the 'good' side in the right orientation.I use the Ultimaker a lot and the Formlabs One which i used a few times to print more complicated parts is not really that much better. And personally i dislike working with resin as it is much to messy. The results from the Formlabs compared to the Ultimaker did not justify for me to purchase it.

author: technotronix
author_rank: Regular Contributor
timestamp: August 05, 2016, 06:44:40 am
content: I found it Accurate and more affordable than before but two thing I am suffering is,Lack of maintenance can suffer from UV instability and can not used in very hot temperature.

author: cram.redan
author_rank: Newbie
timestamp: August 06, 2016, 11:23:49 pm
content: @KorkenI've just received a Formlabs2 SLA printer, with various resin tanks and made some enclosures tests for a product I'm currently designing. The results are pretty damned good (in terms of aesthetics, dimension accuracy), and quite easy to obtain (We had a Kudo Titan3D previously, and this was a nightmare compared to the Formlabs2)After the object has been printed, I keep it in Isopropylic alchool 10 minutes, and then expose it under proper UV lightsource around 60 minutes to have the object fully polymerized/solidified.Then, I start the sanding process by hand under a flow of water (600, 1000,2000,3000 grit paper) depending on the final surface I want to get. It brings a nice and shinny finish to the object, and clears all hangout cut marks.Last but very important step, I use a car polishing product (Novus Plastic Clean & Shine). It's a 3 step process. You polish the object with the first fluid, then the second, then the third.The result : an enclosure that's as professional as a real plastic injected one (but took you 6 hours of your time to finalize !!!). This process and the resulting objects are so good that I went further one step and produced replications of the SLA objects through a "silicone molding & pressure chamber" technique, but this is another story !Formlabs2 printers accomodate for proprietary resins (quite expensive, but with fairly predictable results - no trial & error that drives you mad and pulls your hair out). The Black, Grey and Transparent ones work quite well. They also sell a white and a tough resin (blue) i didn't try yet. The transparent one, provided you properly sand & polish your object, even allows for creating transparent display panels for your plastic enclosures. Tried and it works like a charm as if it were a real acrylic transparent PMMA panel (a little less transparent though to be honnest).I can send some pictures if you want so.All the best, Marc/Paris

author: zapta
author_rank: Super Contributor
timestamp: August 07, 2016, 03:09:21 am
content: Quote from: Korken on August 02, 2016, 05:20:42 pmWhat fdm printer? Some are better then others?Also what box sizes so you print?

author: ChunkyPastaSauce
author_rank: Unknown
timestamp: August 07, 2016, 05:51:27 am
content: Could you upload your model?

author: MicroBlocks
author_rank: Contributor
timestamp: August 07, 2016, 06:14:03 am
content: Currently i am leaning more to make vacuum forming molds with the 3d printer (or in the future with a small cnc).You can then have a smooth finish without all the work to make a 3d print acceptable.A small vacuum forming machine is not difficult to make or buying a small one should not be that expensive.The material could be ABS, Acrylic etc. Lots of colors and material choices.This will also prepare you better for when an enclosure has to be injection molded as no undercutting is permitted.A 3d printer will give you lots of freedom and can produce shapes that are not reproducible by any other process.Seen it many times by enthusiastic designers that wanted to make their design into a product.They had to start all over again. Vacuum forming is inexpensive and forces you to think about manufacturing.Also for small runs it is a perfect way.

author: Korken
author_rank: Regular Contributor
timestamp: August 14, 2016, 07:13:48 pm
content: Quote from: cram.redan on August 06, 2016, 11:23:49 pmVery nice to hear!If you'd like and have time, please upload the results - I am very interested.For post curing, what do you use? I have been looking into building a cure-box as well. Do you have temperature control as they recommend in their whitepaper?Quote from: zapta on August 07, 2016, 03:09:21 amI use an Ultimaker 2+, does a very good job.Generally I never have problems with larger enclosures, it is the small ones that need thin walls that are a problem.I am currently prototyping a case for an RF system working in 3-7 GHz for personal localization, and the case has an effect on the signal if more than about 0.5 - 1mm of material blocks the antenna (which is desired to have concealed).This is in it self not a problem (I generally use the 0.25mm nozzle) but to make it fit well in hand as a "tag" it has curved surfaces which forces me to not have the "top" of the lid/bottom towards the build-plate.With the roof now failing when making it thin, even with a lot of support (to the extent that removing it is somewhat irritating, sometimes damaging).With this I am now testing to print it on an angle, which is more successful, but I have not finished testing.Quote from: ChunkyPastaSauce on August 07, 2016, 05:51:27 amWill do tomorrow, to show an example.The subject is more general though, I still plan to use the Ultimaker for general prototyping - but perhaps use the SLA one for the "final" demo-case.With the SLA resins and resin tanks being quite expensive (seems to be about 4-6 times more expensive to print in an SLA printer), I believe the combination of both to be quite pleasant.Quote from: MicroBlocks on August 07, 2016, 06:14:03 amThis sounds very interesting! Do you have some examples/images to see the result?

author: MicroBlocks
author_rank: Contributor
timestamp: August 15, 2016, 03:36:43 pm
content: I don't have it done yet. My needs are just for small parts so a dentist vacuum forming machine is sufficient.Like this one:They are easily available from ebay/aliexpress.For such a low price (especially compared to a 3d printer) it is no brainer to get some experience.If all goes well and bigger parts are needed then building one is not too difficult.If it works well, then the next step is a pad printer to add a logo and other images/text.The pad printer is currently for me low priority so probably in about 5-6 months.

author: dimbmw
author_rank: Regular Contributor
timestamp: January 02, 2017, 08:14:36 am
content: Quote from: MicroBlocks on August 15, 2016, 03:36:43 pmCould you clarify how this vacuum thing helps you ? Don't you need to 3D print the part first?

author: wraper
author_rank: Unknown
timestamp: January 02, 2017, 08:20:35 am
content: You can use 2 nozzle FDM 3D printer. One of them will print support material. It can be ither one which is easy to separate or dissolve (for more complicated things, where it needs to be internally). There are even PVA filaments which dissolve in water.

author: janoc
author_rank: Super Contributor
timestamp: January 02, 2017, 11:27:03 am
content: Quote from: wraper on January 02, 2017, 08:20:35 amYes, in theory you can do this. In practice it is next to impossible to keep the two independent nozzles aligned properly together (calibrated) because of the arbitrary (and possibly changing!) offsets between the extruders. Most consumer 3D printers lack the sufficient rigidity and mechanical accuracy for obtaining repeatable results using this method. The second extruder/nozzle also tends to reduce your working volume due to the mechanical constraints.That's why the trend is to go away from multiple extruders/nozzles to a single extruder with multiple chambers, like the Diamond hotend that can handle up to 3 filaments at the same time. But those have also their own share of issues (mixing of plastics in the nozzle, possibly different temperatures needed for each, etc.)A way better solution is to design your part to minimize the need for support during the printing, even if that means that the object will have to be glued/screwed together from several pieces.

author: wraper
author_rank: Unknown
timestamp: January 02, 2017, 11:41:02 am
content: My CEL Robox have a head with 2 nozzles, both are heated individually. So there is no problem using 2 different materials.

author: richardlawson1489
author_rank: Regular Contributor
timestamp: January 21, 2017, 02:34:08 pm
content: It was accurate and affordable but one thing I face was temperature issue.