If you want to succeed as an injection mold maker, be prepared for a lot of hard work and effort! The skill required for plastic injection mold making is considerable and you must be prepared to diligently apply yourself, for quite a lengthy period of time.
Not only that, but you must be willing to be instructed, often in less than politically correct methods. There will be sleepless nights spent lamenting why you neglected to do something simple, like check your work or ignoring a dimension on the print.

However, if you are truly motivated and have basic skills, it is entirely possible to learn how to become a successful injection mold maker. It helps to have a mechanical aptitude, but, with enough desire and effort even that can be compensated for.
What You Must Know
The mold making process is quite complex and it can take a lifetime to master only a few of them. One of the more challenging aspects of the trade is the fact that there is almost no end to what you can learn and master.
You will, in the course of time learn about CNC milling, EDM machining, mold polishing, jig grinding, WEDM, CAD mold design, precision grinding and mold assembly. Each of these disciplines takes years to truly master, but once you are successful you will never be unemployed.
Maybe Go Back To School
Many community colleges have evening programs where you can take supplementary courses, such as trigonometry, geometry, physics, CAD design and various machining classes. You can learn surface grinding basics, EDM, CNC machining and lathe work. Other thing to learn include mold polishing, surface finish requirements and mold assembly.
Some innovative companies have formed educational alliances with one another and local schools to educate their workers. This is an excellent method to train highly skilled mold makers. If you are lucky you might even learn a bit about micro-welding services.

Generally, in the United States, you must take classes, either at a technical college, or a night school. This is done in combination with working as an apprentice, usually for 3 or 4 additional years. As mentioned above, some areas have developed new programs to train workers and these have proven to be quite successful.
Personally, I completed a 2 year full-time course at a very good technical college in Minnesota. During this time I worked as a machinist in local shops, which provided great way to learn how to become a successful injection mold maker.
I can’t believe I finished
Upon graduation I was hired as an apprentice mold maker, which offered a great deal of security for me and my young family. Because I had finished my classes during the preceding two I was not required to take any evening courses.
After registering with the state my pay was regulated and my training was somewhat formalized. What this really meant was that I received semi-annual pay raises of around 8% until I reached the journeyman rate, or full-rate. This also ensured that I was trained on every aspect of the trade, though some of the operations the state form included were out of date. Nevertheless, this made things “official” and certainly gave me a sense of security and seriousness.
It was a good thing I had this formal education because it took me a very long time to become proficient as a mold maker. I’m sure my bosses considered letting me go on numerous occasions, to say the least! At one point I even considered letting my trade just become a hobby, like Dr. Hall’s workshop, in Canada.
You need these skills to succeed at injection mold making
Precision Grinding | JIg Grinding | Centerless Grinding | Surface Grinding |
CNC Machining | Manual Milling | Drilling | Mold Polishing |
Lathe Work | Wire EDM | Sinker EDM | CAD Design |
Inspection | Trigonometry | Geometry | Mold Assembly |
Obedience | Working Overtime | MicroWelding | Hot Runner Systems |
Here is an independent review of How To Make Injection Molds. It is by the senior engineer of a world-class mold maker in Connecticut.
The best way to learn how to make a mold for plastic injection is to become an apprentice. If you already are an apprentice, you can learn a great deal from plastics journals, such as Mold making Technology and EDM Today. I believe you can subscribe for free in many cases.