How To Use The Injection Mold Making Process

The injection mold making process must be a great mystery because, over the course of the past 30 some-odd-years I have only met a handful of laymen who understand even the basics. I still find this disappointing; why should something as essential to our modern way of life be so unknown?

Some of the comments I have heard when I tell people that I am an injection mold maker are downright comical. Usually the funniest are from people with graduate degrees; I suppose they have been in school so long they never had time for practical things! They do seem to respond better when I talk about injection mold design, for some reason.

Because I live in a university town and have a number of children, I have a lot of interaction with doctors and professors. Usually I don’t even try to explain, I just tell them something about engineering and industry and they nod their head.

I can’t help but smile when people ask if we “carve” the mold out.

10 Facts about the injection mold making process

• A typical injection mold might take well over 1,000 hours to manufacture. This always draws a frown, how could it take so long?
• Many jobs require over 2,000 hours to build. All this for a cell phone or medical device that is just taken for granted!
• A mold might cost anywhere from $20,000 to $500,00! It’s a wonder things don’t cost more than they do! It also helps to explain why the wages do not really reflect the skill level of the worker. They should be paid more per hour, in reality.
• The individual components of the mold all fit together extremely accurately: typically all the pieces are within a tolerance of .0002 in/.005 mm. This doesn’t mean much, until it is put into perspective. Just imagine taking a cigarette paper and splitting it along the thickness. Now split it again and you have a thickness of .0002 in. That is small!
• Injection mold making requires a wide range of skill and experience. Trigonometry, geometry, metallurgy, computer skills, hydraulics, electronics, hand working skills, and an almost endless amount of machining skills. It literally takes years to acquire the knowledge to master the many facets of injection mold making.

More about injection mold making

• Many mold makers have completed 2 years of technical school, after high school. This is just to get hired as an apprentice. The normal apprenticeship lasts at least 3 more years. This is a rather intense learning period, after which he is becomes a journeyman. This means he is supposed to know most everything, but really, it is just enough to get into a lot of trouble! It takes a lot of concentrated effort to truly master the skills required.
• Some of the smartest people you will ever meet work as mold makers. Some of these guys do things like build airplanes in their spare time. The nature of the trade is to be inventive, so, if they ever have any spare time, you can be sure that most guys are busy making electrical generators powered by the sun or a river, building race car engines, or building a timber-frame house by hand.
• The typical mold maker works a 10 hour day, and often 5 hours on Saturday. Despite the fact that a Chinese tradesman will do approximately the same thing for about $2 per hour, there is still a huge amount of work in certain markets, such as medical.

One time my own mother asked me how many mold we made a day.

• Injection mold making is incredibly global. It is normal to use tools and components from the USA, Europe, and Japan. It is truly remarkable that you can use a machine made in Switzerland, use tooling made in Sweden, cutters made in Japan or Korea, steel made in the US, and it all works, very well.
• Injection mold making has never been successfully unionized. This is highly unlikely in the future either. Most mold makers are quite independent and not the least bit interested in a union. This is a good thing for the consumer, otherwise things made of plastic would be even more expensive! I did work in a union shop once, but it was in name only; mostly to get work from an aerospace company.
• Mold makers are the type of person that would stop to help you, if you had a flat tire on the highway. Not only that, but if you had no jack, they would give you their own! Next time you use something made of plastic, thank an injection mold maker!