The structural composition of the die
The mold is composed of mold frame and mold core and related accessories. The mold frame and accessories are made by professional manufacturers according to the commonly used series specifications for choice. The mold factory generally only does mold core processing and assembly. All kinds of different molds are mainly in the mold core, for different shapes of products, mold designers design the mold core into various forms, such as: Point feed, direct feed, dive feed, slider, core pulling, straight ejection, push plate ejection, secondary ejection, hot runner, gas assistance, etc., the purpose is to be able to shape according to the product design requirements and convenient and complete release of the mold, but also to consider the die core in the processing of easy processing and die service life.
The steel used in each part of the mold is different. The mold frame is generally used in medium carbon steel 45# or 50#, and the accessories are heated with high carbon steel. The steel of the mold core is made of alloy steel with more complex composition, including pre-hardened steel and heat treated steel and mirror steel, etc., and the grades used in different countries are different. NAK80, 718, SKD61 (Japan) P20, H13, (USA) 2344, 2738 (Germany) S136, 8407 (Switzerland), etc.
Now usually say that the mold quality, the main difference in the degree of processing precision mold core and mold the repeated use of life, and largely rely on sophisticated processing equipment and reasonable die structure design, mold manufacturing cycle, of course, is also an important consideration, mould manufacturing cycle because of the complexity of the mold core ranged from 30 days to 90 days (in China), Some in Europe take between 120 and 180 days.
Germany has advantages in precision equipment and excellent steel, but its disadvantages are high labor cost and long manufacturing cycle. China has advantages in low labor cost and short manufacturing cycle, but its disadvantages are not good equipment and relatively low processing precision.
The processing of molds for injection molding of plastic products generally goes through the following steps:
- Mold design (CAD); According to the need to do the product 2D drawing file, in the special mold software Pro/ENGINEER or UD, SolidWorks and so on to establish a 3D model, the analysis to determine the mold structure in all aspects, design the mold assembly drawing and processing detailed drawing, if necessary to simulate the molding analysis.
- The reviewed mold drawings begin the procurement process to purchase molds, core steel, standard accessories, and special auxiliary materials and tools as per the design requirements.
- The mold core needs CNC (numerical control machine tool) processing part of the parts (also known as CAM), first to its programming, there are special mold programming software commonly used, such as UG, Cimatron, etc.
- After rough machining, mold core materials into the processing of each process, generally have CNC milling, ordinary milling, grinding, machining, wire cutting, edm), polishing, benching, some of them want to undertake processing, heat treatment parts according to the different shapes have different processing order, needs to have the professional technicians to plan, is a more complex part of mould manufacturing, It has great influence on the quality, cycle and cost of die.
- After finishing the processing of the mold parts, the mold fitters assemble the mold, during which some parts are reasonably adjusted and trimmed, so that the mold can be opened and pushed out according to the design requirements.
- Mold assembly after the completion of the first use of said test (T1), try to mould fitted with suitable injection molding machine for molding, purpose is to validate the rationality of the design of the mold, the mold validated whether meet the design requirements, the function of adjustment to determine the reasonable forming process parameters, the molding product design and check and identify and adjust the direction of the error.
- According to the results of the mold trial to correct the mold size and rationality, improve the mold cavity finish or surface treatment, letting, etc., after the completion of the mold trial again, repeated several times to meet the design requirements, the mold manufacturing is basically completed.
In general, mold manufacturing is a relatively complex process, so far it still depends on the experience of mold manufacturers, but also the progress, precision, cost of the mold is the main relevant part.