I am looking for a plastic injection molding company to produce some small parts for me. Received a quote from a local company, would like to obtain some more quotes for better price if possible. Any recommendations? I am in California, if that matters.

Also are the molds specific to a type or brand of machine? Or can on set of molds be sent to a different facility and be used without modifications to make the same parts?

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Originally posted by c1steve:
Also are the molds specific to a type or brand of machine? Or can on set of molds be sent to a different facility and be used without modifications to make the same parts?

No input on the 1st question.

The 2nd is a solid schmaybe....
There are standards and most of the time those are mostly ignored when it's inconvenient to follow them- know what I mean?


Tooling isn't cheap. If you're balking at the local place, you can consider the big 'C' location for cost, but it will only be cheaper if you don't have to do it 2x. Tooling is still less of a science than a black art sometimes. You don't leave inexperienced tool & die designers unsupervised, bad things happen.

I'll ask my production guy if he knows any (we're in Kalifornia also). However, would 3D printing be a possibility?

I checked into 3D printing but the cost per unit was high. I am making two parts that will glue together to make a 2" box with rounded corners. Probably will order 1,000 units which should last me a long time. Once the mold is made, my cost per part will be about $1. Also these boxes, I want to be able to make them in both black and white, and some of the other forms of molding were not able to do that.

The supplier that gave me the first quote stated that they will have the mold made in China. It will be a 1+1 cold runner mold, or possibly a 2+2 mold for about 20% more in cost.

With respect to mold genericness...here's the answer I got back...

"Hmmm… long story short, the Mold that shapes the part fits into a Mold Base. That Mold Base can be used with different machines provided a proper adapter setup is used."

A mold can be a serious investment and especially when it will generate just 1000 pieces. Plastics are quite formable and perhaps it would be cheaper to make them from sheet stock.

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Originally posted by David Lee:
A mold can be a serious investment

I grew up around injection molding. My dad was the go to plastics guy in the Kansas City area. As a matter of fact, we helped the inventor of Greenies dog treats develop the process to manufacture the treats.

It depends on the size of the part and the number of cavities. But you could easily be looking at 60k for a smaller part.

Once you have a mold, it can be used in any machine. This is dependent on shot size and clamping pressure. So if your part needs a 400 ton machine, it could run on any 400 ton machine or bigger (just not economical to go bigger).

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The supplier that gave me the first quote stated that they will have the mold made in China.

I can't stress enough how bad of an idea this is.

They are junk and they use junk steel. I don't know of any tool makers in the area that would touch a Chinese made mold if you took it to them for maintenance or repair.

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Also these boxes, I want to be able to make them in both black and white, and some of the other forms of molding were not able to do that.

I don't understand. Changing the color of an injection molded part is incredibly simple. Purge the old color out and put the new color in.

It may not seem like it, but 3D printing is going to be your best option. You don't build a mold unless you are cranking out a million parts a year.

Well I received a call today where a customer may be ordering a huge amount, 100k or more. So I will see how that plans out. Strange how one day I made the decision to have a mold made, and two days later I get a call on a huge order. Normally I would only use or sell a few hundred a year.

Thanks for the tips on the Chinese molds. I will ask the local shop to give me a quote on a USA made mold.

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Also these boxes, I want to be able to make them in both black and white, and some of the other forms of molding were not able to do that.

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I don't understand. Changing the color of an injection molded part is incredibly simple. Purge the old color out and put the new color in.

That was in regards to other types of molding. My notes mention FDM printing, MJF, and RTF molds.

Check out Accumold in Ankeny, IA. Knew someone through the shooting community that worked there, just don't know if he still does.

https://www.accu-mold.com/

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I will ask the local shop to give me a quote on a USA made mold.

Make sure you are sitting down when you get it.

Have you considered doing this yourself? For years my dad had a very old,small machine ( Like this) in our garage cranking out parts for a loyal customer of his. Prices on used machines isn't bad.

I would also price around the mold and molding company in the Midwest. Even with shipping you will probably be saving money.

The "typical" way to do this is that you work with an injection molding company on the design, tooling cost, piece cost, etc. Then they will go out and get the tooling made.

Be sure it is clearly specified in a legal agreement with your supplier as to who owns the mold. Even though you paid big bucks to have the mold made, if its not spelled out and you want to take the tooling elsewhere, they may well claim it is THEIR tooling. It can be a costly mistake

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Originally posted by WildSig:
Check out Accumold in Ankeny, IA. Knew someone through the shooting community that worked there, just don't know if he still does.

https://www.accu-mold.com/

My neighbor is the CFO at Accumold - nexr door neighbor is the IT guy there. Email me if you want and I can check it out for you. Although I think they mostly do very small pieces - smaller than a penny.

I'm just getting into some learning about injection molding, so I don't have a lot to offer. What I can offer, though, is that there's a crowd in Raleigh NC (I think) called Protolabs. My previous employer had some goods made there with success. There's also a company in Greensboro -- I think they're called Bright, I'll look into it -- who does injection molding. I know a company who has contracted with them to do some molding, based on good samples.

ETA: Bright link
ETA: Protolabs link

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Be sure it is clearly specified in a legal agreement with your supplier as to who owns the mold. Even though you paid big bucks to have the mold made, if its not spelled out and you want to take the tooling elsewhere, they may well claim it is THEIR tooling. It can be a costly mistake

Very good point! I completely forgot about that.

For a 1000 part run an aluminum mold may be satisfactory. Much cheaper.

Or make cavities that fit into a quick change mold base.

Bob

Thanks for all the help. Thinking about it, I should have the shop that does the molding order the mold itself. That way they will work with the machine shop to make sure it is built correctly.

Definitely will have the ownership of the mold clearly stated in the contract. So if members have general recommendations for injection molding shops, I will ask for estimates from multiple molders.

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Originally posted by c1steve:
Definitely will have the ownership of the mold clearly stated in the contract. So if members have general recommendations for injection molding shops, I will ask for estimates from multiple molders.

I bought plastic parts for General Electric, Housewares Division for a while, back in the day, and can confirm tooling ownership and inter-operability are intricately detailed discussions.

As has been pointed out above, just paying tooling charges does not mean you then own the tools.

Make sure that you fully understand which molding machine(s) - both manufacturer and model - the tooling is designed to work with, whether amending these tools for other machines is feasible or not, and if so, which tooling servicing companies would do the work. (A truly diligent buyer would then contact one of those companies, verify their ability to do the mods and get a ballpark of the costs and timeframe involved.)

You would then have a set of tools that work with machine set A, with an idea of what would be involved if you had to move to a different vendor who used machine set B.

Assuming you are happy with the information, and proceed, make sure ownership status and machine compatibility are both spelled out explicitly in the contract.

Also, think about the payment terms for the tooling. For new tools, we generally held back a good chunk of the tooling payment until after we had gotten adequate samples from the tooling and our engineering department had confirmed dimensions and variance on key dimensions via detailed 'first article' inspections.

I work with UPM in Baldwin Park, CA. They do customer molds. I've worked with a few others in SoCal, but they produce their own product (medical, etc).