3D printing is great for most things, and I certainly abuse my Polyprinter 229, but sometimes you need something too intricate or in to many quantities.
I’ve been getting quotes from injection molding companies, but it seems there are two models in the market.
Get started for under $10,000 but pay 10-100x the cost per unit
Get started for over $100,000 for a simple part, but get the unit cost way down (to like 3D printing cost)
Does anyone know any providers that will do reasonably priced aluminum molds and not charge me $1.00 a piece for 0.62 gram parts that are basically an open sides square less than an inch in size?
I would love to know who you have worked with, and any gotcha’s you ran into.
As far as I know these guys are one of the most adorable low volume injection molding company in US:
I am sure there is some company oversees that will do a similar service but finding them is the hard part. Another strategy I am told is effective is to find a mom and pop machine shop that has an underutilized injection modeling machine laying around and pay them to run the parts and make the mold.
You can also go with a desktop injection molding machine like this one:
This said you will likely need to do all of mold design work yourself at this price point.
Good luck,
10K for an injection mold run isn’t outrageous. Personally, if you have a very simple part, I would suggest searching alibaba.com for similar items. You can often find a supplier that may make a compatible option that you could design around. I did this with alternative form factor batteries a few years back, contacted a supplier of the normal form factor batteries and found that they also made specialty options and was able to catch some of those without the setup costs required.
There’s a guy who started making LEGO compatible military weapons and clothing as a hobby (rather than the pseudo-ambiguous weapons that LEGO makes). I’m talking a LEGO-figure-sized AK-47, grenades, helmets, etc.
He’s expanded considerably but may be able to guide you. His stuff started as a niche market and he was doing very small runs of injection molded stuff.
Thanks I will certainly look at those options. I do understand $10,000 is a decent starting point. What gets me is that there doesn’t seem to be any middle point. I can do $10,000 for 10,000 parts, or I can do $100,000 for 1,000,000 parts. But there is no in the middle price points.
From my understanding the cost difference is a function of the tooling required. The primary cost of injection molding it tool used to make the part as it has to be custom made for each part produced and the setup of machine to run your parts. If the tool is made out of aluminum it is relatively easy to make but has a short life. However for a hard tool the cost to produce as well as the skill required of the designer goes up dramatically while setup time cost say about the same.
If we assume ABS cost $6 a KG in bulk you are looking at materials cost of $0.006 per part at 10,000 parts you would be spending $60 in materials for the parts.
What cost money is the setup and the tool, the parts are practically free.
Vincent R. Gingery’s book “Plastic Injection Molding” has plans on how to build a DIY plastic injection molding machine. He does not mention the price but it looks like it would be very much less than $10,000, maybe even less than $1,000.
The die making is the expensive part. For 10K, you are paying up front. For the high per part price, you are either building die finance costs into the per part, or someone has figured out how to build small run dies cheaply, and I’m not aware of anyone who has done that.
You might be able to negotiate a middle ground, 5K up front, and a bit under half the no up front per part price, but I wouldn’t count on it.
On the other hand, if you find an off shore company, and can deal with the language challenges and holidays, you might get the mold fees under $5K, and get the low per part price.
In any case, if this looks like a potential long term run, don’t forget to build the second die set into you upstream pricing. You don’t want surprises when the first die wears out.