Hello everyone I was wondering if anyone had any advice about compatibility of Pla plastics and composites. I’m thinking about printing molds for small parts for my car or just plugs to wrap with composites for strength and heat resistance.
Truthfully as far as composites go I’m a beginner have read fiberglass and other composite materials a few times over the years, so I know the theory, but not much hands on experience, but I would like to make some decent looking parts!
Thanks
Don’t forget that plastics can shrink or deform with heat. I’ve done something very similar, scanned a car, designed a part, printed it, then made a mold of it.
I printed the part in ABS then put a “skin coat” of body filler over it to smooth everything out for molding. I wouldn’t trust a 3D printer to make the mold itself.
Nice thing about PLA is that you can wash it away. I’m doing some experimentation using PLA tooling for wash out parts. For a female mold you’d rather be using ABS as weasel said. You can also print and then do a PFP mold. I’d think the abs would be ok if released first but many of the less expensive 3d printers don’t have the best resolution for the surface. This may or may not be an issue but, could cause release problems.
Also PLA has a melt point of about 300degrees, so not horrid for heat resistance.
We’ve used numerous 3D prints as masters/plugs, but never for moulds. Material availability and choice has improved since the OP so it would be interesting to see any feedback today
Would lamination over 3D printed parts cause issues with bonding and also de lamination since most are made of some type of plastic?
Never caused us any issues using them as patterns. We have used many in their raw state too, with no primer application and have not had any pre-release or unwanted bonding
Should work fine as iWeasel4 said - print then fill deviations with a filler of sorts, bodyfiller, duratec if its fine, etc.
Obviously anything more than room temp resins are likely no good with standard printed materials. Some have higher Tgs but unless your going with metallic printing or some higher Tg polymers, stay away from anything but room temp resins. Also probably good to avoid high exotherm resins
Are you talking about PVA as a filament and wash it away with hot water?
PLA is dissolvable in a certain alcohol, I forgot which one.
yes you’re right, not PLA… HIPS. Or styrene is what I found that would work. Has decent heat deflection, 189F. Not sure what PLA deflection temp is but, PLA would also work.
I’ve used 3d printed Nylon in parts as internal piece. Have also made small molds form 3d prints. There are larger machines in development to print extra large things like 30x30x15 or more. I also have seen that robotic arm that uses carbon fiber thermoplatstic to print parts.
The main thing is getting the right geometry for the final part. For high tolerance applications the part would need to be printed then milled to the right shape. Thermwood is making a large format machine like this. It has an extruder and mill head. Then you would be able to print say a fuselage plug.
I’m most excited for the possibility of making large molds though.
I do have a small machine i recently bought for making small uav/quad copters. I have some HIPS to make some internal mandrel type parts as well as some high temp PLA. With the new baby haven’t had much time to work on my stuff…
I’ve used SLS nylon 3d prints for both mold masters and actual molds, even for 310 degree prepreg. You do have to be careful about distortion. If there’s a flat edge to the mold you can clamp or glue that to a known flat surface for making the epoxy molds. Seems like smaller and thicker parts distort less.
I use abs plastic out of consumer grade printers for plug construction. First picture is after bonding pieces together with ABS cement, light 220 grit sanding, a filling with a plastic body filler. The second picture is after a lot of block sanding, duratec primer, more sanding, and polishing:
Depending on the direction the layers are running in your 3d print- do not oversand the surface. You will end up with papery thing partial layers and they will want to flake off of the surface and become very sensitive to temp fluctuations. Also, acetone vapor baths work really well with ABS (and make the part stronger).
Maybe I’m missing something. If you are milling anyway, why bother with the 3D printing? There are plenty of very stable tooling materials that you could machine to a high tolerance to make patterns.
I think you would be milling in areas where you have an extra high tolerance beyond that of the 3d printer.
The main advantage being less waste by using additive manufacturing over subtractive.
Less waste but at what cost? How much does it cost to run a 3d printer and then a mill in terms of time and material vs just milling out of tooling board or some other substrate. I’ll admit I have no experience with 3D printing but it seems like a lot of steps to save a couple of dollars on the subtractive products.
I’ve had great success building up the substrate rather than trying to cut something out of a solid block. For instance, a tooling project we just finished was approximately 98" long by 39" wide by 18" high for the main body and then there was a flange around the bottom of the part as well as a flange for the mold that added another 32" to the overall dimensions (130" x 71"). I didn’t cut the pattern out of a single block of tooling board, rather I built a shell from 4" thick sheets for the main body and the flange areas were built of MDF. That saves a tremendous amount of material. After the build-up, we milled it on the router in about 6 hours. How long would it take to build something like that with a 3D printer? And then run the router over it to bring it to spec. I don’t think the routing time would be much less. I haven’t any idea how long it would take to print.
Now I know 3D printers don’t have that big of an envelope but I think the principal remains the same whether 8 feet long or eight inches.
I can certainly see the value in building a one-off part for demonstration or proof of concept type work but I just don’t see it when you are building a pattern that you are going to mill anyway.
I’m always looking for better ways to do things. Are there any printers that you could go from printer to mold building with any amount of accuracy? It would definitely be great to print a “ready to mold” pattern. Or even one that just required some Duratec and finish sanding.
As previously mentioned, personally we have on a numerous occasions used 3D prints as patterns with no secondary machining required. 3D printing is far more accurate than it used to be, with many material options now available.
The earlier prints were all coated in Durabuild, but the more recent ones were just flanged up and moulds pulled.
With regards to the 3D print, it can be used as a prototype. Lets say for example you require a small moulding for a car, we would create the model, have it printed and offered up to any interfacing components. This for us proves the item. We are then ready for tooling manufacture using the prototype unit. It works very well for many of our applications. Whilst the print is being carried out our operators can be doing other tasks that aren’t machine driven
Yah I would say it’s more for prototyping, which is what I do generally.
For this purpose it would be very useful. The technology is still getting more and more accurate and faster. When the process is faster than milling, than yes, it would be extremely useful.
The extra large machines, like 10’x 20’, are not quite there yet. But are in development. Obviously they’ll be expensive in the beginning but will decrease over time.
As with any technology or process, they have their place and own advantages. We already uses printed technology in our builds and I’m sure more will continue to be put into use as the technology develops from prototyping into the production environment.
Already the jet industry is moving toward using printed parts in their production which is extremely high tolerance and tends to be exotic alloys.
Interesting to see how this technology develops.