Greetings, we are working on a project which was 2 small 4"X4"ish brackets, Not particularly complicated in shape. the brackets hold < 1 pound, and are not particularly critical to dimensional repeatability (somewhere around +/-.01" tolerance). I’m not particularly familiar with what is available in 3D printing, but it looks like the ultimate prototyping device, and maybe also for preproduction units of <100. Wondering if the forum would care to comment on who their favorite 3D printing facility in the US is, and whether or not the costs would be similar to machining, and where a typical break even is between the cost of a dedicated mold vs 3D printing for ABS material.
Thanks,
-Craig
2 Likes
Craig Hi,
We can help you but based in Kolhapur India.
For small quantity 3DP is suitable Faster & Economical option & go for it.
According to your application right plastic composite can be selected like tough/wear resisting etc.
Regards
Paresh
cobnut
3
@ccgoudie a key factor in the decision between molding and printing is whether you think the design will change. Injection molding is great if you want many 100s of a piece that’s always going to be the same (and far more economical than 3D printing in that situation), but it’ll quickly become less economic if you need to make changes to the design. Reading between the lines of your post, I’d suggest there’s a good chance the design may be tweaked so I’d lean towards a 3D printer to help finish that design before moving to another production process with a model that’s finalised.
However, there could be an issue with 3D printing in terms of the model itself. If you go down the FDM route (which is the cheapest), you could end up with some very nice models that should be able to meet your dimensional accuracy requirements but only just. 0.01" = 0.254mm, which is actually quite tight for FDM printing, but it is achievable, especially if you’re repeating the same model and can tweak the dimensions to match the output of the printer (i.e. if it’s 0.3mm too wide when printed, make it 0.3mm narrower in the model). The issue is mainly in isotropy. FDM printing works by putting down successive layers of plastic that bond together, but depending upon the model itself and the direction of printing, those bonds can be a point of failure. The problem is explained nicely here (even allowing for the fact that Form sell SLA printers, so are a little biased, the problem is a real one). This means you may find strength issues with your brackets if FDM printed, and there’s no guarantee those issues would exist in an injection molded piece. You could buy an SLA printer such as the Form 2, but that’s going to increase your costs of printing and, to be honest, may still not be representative of a finished molded piece.
My advice would be to choose a Hub here, maybe two or three, and get prints of your model from each of them, stressing in your order that the bracket must support weight and in which axes, and stressing the dimensional accuracy issue. Once you have the prints, look for stress failures, accuracy, etc. and see if you can modify the design to reduce the problem, then rinse and repeat. Small objects like these brackets should be fairly low-cost to get printed here, so the outlay in these test prints will be worth the money. If you find the 3D prints work OK, then I’d suggest going with a 3D printer yourselves. Not only will that allow you to change the design as often as you want, you’re surely find other uses for it over time. If the prints don’t work (and you’re sure it’s a technology issue, not a poor product from the Hub) then maybe molding is the way to go.
2 Likes
Gutti
5
Craig,
Please contact me on: gustav.liljeqvist@core3d.fi or info@core3d.fi
More info: www.core3d.fi
All the best
Gustav
Hi,
3D printing is the cheapest/part and great for prototyping. You can also make your pre-production if cost is a major factor.
Otherwise, cold injection in polyrurethane is great for pre-production if mechanicals properties need to be really similar to an injected part. You only need to pay the cavitiy, not the tooling. On the otherhand, parts are expensive. A injection mold should only be considered for mass production.
Contact me if you need something, we can 3d print or design cavity and the injection mold.
nicolasdefoy@yahoo.ca
Cobnut explained it great +1
