AISI 1050 Steel for Injection Molding

Is AISI 1050 steel a good choice for making custom injection molds? I have a client that received a very low quote for custom injection molds from a Chinese source. I'm skeptical, so I asked a variety of questions including the material that will be used. They answered with 1050 steel. I have been searching for some information pertaining to 1050 and mold making, but it doesn't seem to be commonly used for this purpose. Can anyone offer any insights?

Reply to
John Eric Voltin
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"Can anyone offer any insights?"

yes, getting involved in injection molding with:

very little (or no) injection molding experience, a client who appears driven by price alone & a vendor w/o a stellar track record

is a great way to REALLY learn the process by trial & error.

when it's all over you know a whole lot about injection molding

your situation has most, if not all, of the initial condtions for a disaater

How many injection molded parts / molds have you been involved with?

I've done only a couple & my first thought would be hire a competent tool maker to make the mold & give to a competent shop to make the parts.

what material are you shooting? desired / expected tool life (shots)? single cavity? multiple? how many?

has this thing ever been made before?

successful mold making requires a competent mold designer and / or a competent tool maker

you might be able to "contract" your way out of this by putting all the risk on the mold mfr (esp) if they're the company doing the production runs

progess payments for the mold dependent on producing XXX? good parts

tell your client this............................................................

"the bitterness of poor quality is remembered long after the sweetness of low price has faded"

cheers Bob

Reply to

Here's one of numerous listings for this mid carbon manganese containing steel.

Because it is a carbon steel it is susceptible to heat treatment.

If you are talking plastic injection molds, there is no reason this should not work quite well. Zinc alloys might demand more consideration.

Brian Whatcott

Reply to
Brian Whatcott


Thanks for your input. I realize that my posting was very brief and failed to provide much detail. The parts in question are generally ABS (one acrylic and one PE) and range in size from a few inches to 30 inches. These parts need to be high quality with good tolerances and nice, professional surface finishes. The production volume isn't terribly high - about 10,000 pieces per year. Therefore, single cavity tools should be fine. Family tools are appropriate for some of the similar parts. The tools should last about ten years - so 100,000 minimum life. I would suggest a 500,000 lifetime guarantee. These are parts for a new product, so they have not been made previously.

I have been working with injection molded parts for years and have worked with a variety of reputable mold makers, including a few overseas. I am not a mold designer or mold maker myself. My job is to design the parts, make certain they can be molded without undue difficulty, and work with the mold designer/maker to provide any necessary support. My current client has received tooling and production quotes from a company I know nothing about, but their pricing is surprisingly (unreasonably - in my opinion) low. This concerns me a great deal, so I'm investigating their proposal. When asked, they stated that all of the tooling would be made from 1050 steel. Since no company I have ever worked with has even mentioned using 1050 steel, I started looking for information. My references don't mention using 1050 steel for mold making and a web search produced one company in China that uses 1050 for mold bases (inserts, etc. are made from other steels).

I am suspicious that using this low priced approach will lead to unacceptable quality and/or unexpected costs. Of course, my instinct tells me that this would be an enormous disaster as you have suggested.

Since my job is to provide technical knowledge and advice to my clients, I am looking for clear technical reasons why using the cheapest sources is not wise. So far, the argument that this pricing is unreasonable/unbelievable/impossible has not been very convincing.

Reply to
John Eric Voltin

I am talking about plastic injection molding, primarily for ABS plastic (also a little acrylic and PE).

I'm particularly concerned about the wear of such tools over time. My general understanding is that tools made from cheap steels don't hold their geometry as well as high quality steels. There may also be issues pertaining to the process of making the tools, but I'm not an experienced tool maker.

The following is a note I received from someone knowledgeable of tool making and who has seen the parts in question.

1050 steel is what they call 45 steel in China. It is plain carbon steel and is only used for inexpensive, non-critical parts or for low pressure forming. Our factory will not use this material, for these molds especially given the size and required clamping pressure on the larger parts. As I have mentioned, we use 718 steel, which is imported from Switzerland. The 718 steel is in the same category as P-20 (40CrMnMo7) but it is a higher grade tool steel than P-20.
Reply to
John Eric Voltin

1050 is a high carbon steel. It should have good strength properties, but it won't have the wear characteristics that tool steels do.
Reply to
Jeff Finlayson

Thanks. This is what I expected.

Reply to
John Eric Voltin

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