For those companies who had their injection mold making project proceed in China which is far away from their countries, deep understanding of the actual process of mold manufacturing is an advantage to get the project under tight control, sitting in the office and simply wait for a final result from the mold making company is always not a good way to go, It would be too late to do anything if don't manage your project step by step.
A mold project includes design, steel preparation, rough machine, precision machine, fitting and mold trail.
1) CAD design
The design is started with a 2d layout, basic mold design information will be present, such as mold size, gating way, parting line, ejection way, cavities layout, mechanical design, accessories used, steel of each component used, etc. 3D design in details and NC programming will follow after the 2d design is approved by the customer. Depends on the complexity, a complete mold design would need 3-7 days. Some of the complex projects require mold flow analysis or frequent updates of custom design, it could take much more time.
2) Mold base, steel and accessories preparation
Mold base and steel can be ordered immediately after design get confirm, accessories especially hot runner system could take much longer time to get back, all of this procedure need to be track closely if you don't want to cause any delay on next step.
3) Rough machine
The steel need first to be sized, milling, drilling, lather are the main process way to get the rough shape or the cavity /core. Normally 0.15-0.3 mm steel left for precision machining later.
4) Heat treatment
After rough machining, internal stress would be created during machining, do heat treatment to get certain hardness and internal balance, such as 1.2343, 1.2344, it usually need to be harden to HRC40+, some of the steel don't need it, like P20, 1.2312 etc.
5) CNC precision machining
To get designed dimension, the CNC process of precision machining is much slower than rough machining, also the steel hardness is much higher.
6) Wire cut and EDM
Wire cut is a process specially for holes (ejector pin holes, lifters, inserts), EDM is particularly for some of the area that can't not be machined by normal way, either too small to allow the cutting tool work properly, or it's too narrow to get there.Injection mold trial running
7) Finish and fitting
After all the components are finished and prepared, mold maker collects them all and assemble them by following the design drawing, it's a job rely heavily on experiences and skills, some of the part might need to be polished to fit, or the core or cavity have specially requirement for surface finish, such as texture, polish, engraving.
8) Mold trial
Congratulation if it's still on schedule as planning, it's the time to get the mold on an injection molding machine to do the trial. Make sure you made your requirement clear how many plastic parts you need for samples, instruct the mold making company to use the right resin, injection parameter and measurement report should be provided along with molded plastic parts.