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Injection Molding Questions from a customer standpoint

Jay Fleming

Hot Rolled
Joined
Aug 7, 2014
Location
Noble, OK
There isn't an injection molding subforum, so hopefully this will work.

My wife wants to develop a household item that would be best suited to manufacture via injection molding, so I'm working on the preliminary stuff.

I've contacted a few shops and have received one quote so far. The quote received was from a more "PROTO"type shop it seems with a significant web interface. I'm not going to name names though. The quote I received seemed to be significantly higher than expected, especially for the mold making. Am I missing something as far as the quality the mold needs to be? There are three different parts and I was quoted $5k for a mold for a part that is less than 4"x3"x.5". I can't really say what the parts is, but we'll say it is shaped like a hook from a clothes hanger. I haven't received a quote back yet from what I feel would be a more down to earth IM shop, so I have no comparison.

Does anyone here do a lot of mold making and can tell me if this is a reasonable price?

Are there any representatives for IM shops here on PM that I can talk to about quotes?

Thanks.

Jay
 
$5k isn't much but it really depends on what you are getting, and what you want. Aluminum molds are my favorite, both to make and run. Are all three parts moldable? If so can they all be put in the same mold, ie be made from the same plastic?
 
I've designed parts for injection molding and seen the quotes for tooling. I'll just say $5k for a single cavity mold does not shock me. I've seen large molds that cost $100k and up.
Interesting. Good to know at least.

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$5k isn't much but it really depends on what you are getting, and what you want. Aluminum molds are my favorite, both to make and run. Are all three parts moldable? If so can they all be put in the same mold, ie be made from the same plastic?
My original intention was to have all 3 pieces in the same mold to where they would break apart by the end user for final assembly. The outfit said they can't do it that way, which strikes me as odd, but it has more to do with the way they quote electronically.

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the price of 5k is normal,maybe even a tad cheap,yes even for one part. as long as the parts are somewhat similar in size and height,and of course, same plastic, they can all go in one mold. but be careful what you get. some hack shops make garbage molds that flash (leaks at Parting Line), have poor cooling lines, and crappy steel that wont survive long in the Mold Press. the range between a cheesy mold and high quality mold is far apart. (used to make plastic inj. molds for 20 years)
 
Jay,

Welcome to the world of product development. (insert half a smiley) Yes, it can cost 10,000's of dollars to get even a simple-cheap-and-cheerful product ready for production. Ask me about my $400 prototype sheet metal brackets (estimated production cost in modest volume: well under $2). Tooling is expensive, and you pay for it all right up front before you ever know you'll make any sales.

$5,000 does not sound terribly high for a mold, although another shop probably can quote it lower based on your rough description of the part complexity. Doesn't do you any good in this instance, but that same $5,000 would probably buy you a more complex part at the same vendor. If you are hinting at the same PROTO vendor everyone here is familiar with, you get some intangibles, namely that the mold will definitely work with the injection machines. Being in the middle between independent mold makers and molders can be an aggravating situation.
 
That is a good deal for a high-quality mold by an American tool maker.

You can probably get it made for half that if you go to the bad place.
 
For what it's worth, between 3 molds; the one given already, one for a part that is 1"x2"x1/2" and one that is 16"x8"x1/2", the total mold price was about $23,000. The per part price seemed high at about $6 for the three parts at 1000 units. This is probably not going to happen. It's a unique enough product that it might be able to sell for $7-8 but after shipping and packaging, I'm already upside down. And I refuse to go overseas for something like this.

Edit: the per part price was after the mold cost. So the first 1000 would cost $23-30 each.
 
Volume is EVERYTHING. At 10,000 parts it might be just $2 a set, at 100,000 it could be $0.75 a set. At a million you'd probably be shocked at how low it would go.

Another thing to remember. It is VERY easy to design an expensive to mold part, and often quite difficult to design one cheap to mold. I would approach other vendors and see if any of them can recommend changes to get the price where you need it.
 
Three molds is not unreasonable, particularly with the size differences. The size of the part dictates the size of the press it can be run in. The two smaller part could possibly be run in a family mold, but balance would be a problem. Your $23,000 isn't unreasonable.

For prototype parts can you make the parts in a rubber mold? What material do you want to run? How about SLA?

Tom
 
Those "get your prototype done FAST' outfits sell speed, not price. Lots of considerations developing a molded part; mold design dictates both cycle time and post molding handling,packing, etc. Plus, while I realize you only want to test the waters, but 1000 parts is only one shift, if that. That is going to incur a set-up charge, for sure. We don't do custom molding, but if someone places a rush order that makes us pull a mold to hang another, we add four hours just for set-up, then setting up the job we pulled again. Sounds like because of different part sizes you have three molds, which may be happiest in three different size presses, so THREE set-ups.

The old traditional way to approach this is to talk to a custom molder, not the toolmaker. The molder will offer guidance as to what material the mold should be (aluminium, P-20 pre hard, or fully hardened tool steel) gating (sprue direct to part, cheap, but expensive to have someone de-gate each part, conventional runner and tab gates, or a hot tip) and mold bases (many molders use at least some Master Unit Die sets, which save part of the cost of the mold base) but not all molders use the same size. Once you get a molder to agree to run the job, they will contract with a toolshop that can do the tooling, and get it right.

Which brings up the point... unless you have some familiarity with injection molding, don't even think of building your own. There are all sorts of nuances that only become evident upon test shooting, and you get charged by the hour plus set-ups for the press time for test shots.

Dennis
 
As others have said, the prices you have are not out of the realm of possibility. It's hard to tell without seeing the parts whether they could be all run in the same tool if they are being made out of the same type of plastic. We do prototyping and mold building as well and our first step in the developement process is to 3D print the said new product. We have a SLA printer and it allows us to make accurate changes to sizes for fit. When we're happy with fit and function we will build an aluminum tool for injection molding. We have had aluminum molds last several hundred thousand cycles which is enough to determine how big a seller your product is going to be. Should a multi cavity, high production quality mold be needed to keep up with demand, you should have time to get it going before the aluminum prototype gives up the ghost. We are a captive molder (we only develope our own products,no outside work) but if I can help you with advise I will. Good luck! The developement process can be daunting. We are working on a product now that has been in the works for going on 2 years and we are still in the prototype mold phase.
 
That is a good deal for a high-quality mold by an American tool maker.

You can probably get it made for half that if you go to the bad place.

And if you go to the "bad place" you better have the machinery and tooling (nevermind the expertise) to rework the runner/nozzles/shut off faces/etc when the mould won't shoot properly. $5k is very cheap for an injection mould. Someone with zero experience thinks the price is high, surprise surprise. Some people just have the default mentality that every price they see is "high".
 
I appreciate the information (almost) everyone. I guess it would have been wise to ask about what to expect of the mold cost first so I wouldn't waste any mold shops' time. I cant foresee what the estimated sales might be, so I definitely can't hope to spread the mold cost out over 100,000 parts.

RC Mech, plain and simple, GFYS. Maybe I should have changed my wording to "more expensive than I can justify with projected sales" rather than "sounds high". Happy?
 
RC Mech, plain and simple, GFYS. Maybe I should have changed my wording to "more expensive than I can justify with projected sales" rather than "sounds high". Happy?

I went back and read "RC Mechanics" post, nowhere do I see any writings justifying your vicious reply.
 
I went back and read "RC Mechanics" post, nowhere do I see any writings justifying your vicious reply.

"Someone with zero experience thinks the price is high, surprise surprise. Some people just have the default mentality that every price they see is "high"."

Vicious reply? I replied to a generalization that was intended to encompass me. If you don't think that was justifiable, move along. There were 10 other replies to my question telling me what I found is what to expect and I thanked them. You didn't notice that did you?

My understanding of how molds are made and priced was unclear, which is why I asked. We're all manufacturers here, so I looked at the mold making process of taking a negative of my part and machining that cavity into two chunks of aluminum. An hour of CAM and a couple hours of machining does not justify $5k to me. So there has to be more right? Or are mold makers doubling and tripling their cost because they can?
 
RC Mech, plain and simple, GFYS. Maybe I should have changed my wording to "more expensive than I can justify with projected sales" rather than "sounds high". Happy?

That's way out of line, especially coming from somebody who has zero experience dealing with mold makers/molders.

My understanding of how molds are made and priced was unclear, which is why I asked. We're all manufacturers here, so I looked at the mold making process of taking a negative of my part and machining that cavity into two chunks of aluminum. An hour of CAM and a couple hours of machining does not justify $5k to me. So there has to be more right? Or are mold makers doubling and tripling their cost because they can?

If it were that easy we'd all be moldmakers. I have made a few plastic injection molds in the past, if it were that easy and profitable i'd still be doing it. I wouldn't touch a mold with a 10' pole again.

If you think it's that easy then make your own molds. Then when the mold keeps coming back because you have to fix this problem, then that problem etc you'll understand what it takes to make a mold. Then you'll happily pay a moldmaker to make your molds because your not capable of making a mold yourself. Harsh maybe, but that's the reality.
 








 
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