New Understanding of Toyota’s Tooling Technology Development
The mold design and manufacturing technology of Toyota Motor Corporation is world-class, and its management and technology have many distinctive features. Through the development of Toyota, we have a new understanding of tooling technology developments.
Mold development and making is more and more dependent on high technology, which can substantially reduce manual labor. The most important factor for automotive mold manufacturing is high quality and a short lead time; the pursuit of efficiency is far greater than the cost. For over a decade, the technological progress we have introduced through equipment and hardware is not enough to compensate for the new gaps represented by the pursuit of technological progress. Here we share the technology development trend we have observed in the development of Toyota’s mold design & manufacturing, for reference and discussion by the industry.
1: The key is the development of computer-aided design software technology
Toyota’s mold manufacturing technology highlights the application of computer-aided design software, and the transfer from production site to computer. CAD product design software, plus CNC programming CAM software, replace manual prototype manufacturing and machine operation. Best mold design and CNC programming greatly reduce the fitter’s workload, and high-precision machining replaces mold development and repair. Now we see the CNC programmer’s capacity exceeding that of site operators, and the labour/hour costs of NC programming exceeding the machining tool time cost by 50%; the programming cycle has surpassed the machining cycle.
With the development of computer technology applications, mold manufacturing has changed from purely human-skill to CNC programming and semi-automatic production. This kind of high precision and unmanned processing has substantially improved the quality of mold and products, dramatically shortened the production cycle, and allowed mold manufacturing technology to reach new heights.
2: Elimination of fitters.
It was originally thought impossible for molds to produce single pieces and complex shapes without handwork, but Toyota proposed to eliminate the need for benchwork. The main purpose of cutting out benchwork is to reduce, or completely avoid, grinding and adjusting tool fitting (assembly benchwork is still necessary). As mentioned earlier, Toyota’s goal has been essentially achieved. Except for tasks such as grinding the surface parting line and convex radius, grinding, mold repair and detail-fixing are mostly now abnormal, or compensate for defects of design and manufacture – which is no longer a necessary and normal part of the job. For example, the smoothness of the mold parting line surface has always been the quality standard we emphasize. In the past, it was mainly fixed by hand to achieve this. Toyota uses high-speed, high-precision 3- and 5-axis milling to obtain a high-precision performance, and to avoid manual work for small-detail tool fitting, while other parting line surfaces do not need to be fixed by grinding. The results show that although the mold parting line curve does not have a smooth finish (with knife marks within 2um parameters), even car components with high-quality requirements have no adverse effects on cosmetic parts except some scratch marks on the inner surface. It is said that some automotive mold factories in Germany, Japan and the United States have already abolished parting line fitting.Similarly, for the shut-off and deep cavity of the tool to be cleared, using high speed CNC machines for cutting the surface, and making the EDM master and proceeding with mirror EDM burning for clearance of the uneven surface and deep ribs by using the Erowa system, and so on, gives a superior matching accuracy and nice finish of the parting line of the cavity and core on the tool. Therefore, in conclusion, the elimination of benchwork is no longer a dream.
3: Integrated processing
There are three kinds of CNC machining lines in Toyota’s machining workshop: the first is a machining line composed of several machines with interchangeable tools. One line includes surface machining, horizontal milling, rough milling and fine milling of all kinds of machines. The matching division of labor is clear, and there is no need to reinstall and correct the workpiece when changing the machine for the next step. The second is the automated flexible machining group with three-dimensional warehouse. The third is an integration of rough steel cut, high-speed, high-precision and five-axis CNC machining center and EDM machines, which has only been put into use in recent years.
- The first machining line, with a single machine for each process which we use at present, utilizes a multi-working machine tool, which doesn’t need to re-set up every time, giving a very high efficiency. There are many mold factories in China using systems such as Erowa/3R, and so on.
- For the flexible machining group (working station), although it’s very advanced, the operation is more complicated, with a longer preparation and work time, making this more suitable for large-scale projects.
- The integrated machining group is the latest technology currently being developed; it integrates the advantages of all kinds of machine tools (except for bottom processing) – raw material cutting, final finishing, parallel cutting, high efficiency, precision tolerance, high speed and so on. Everything is proficient, processing efficiency is very high. The disadvantage is that the cost of machine tools and the need for environmental requirements are both very high. In a competitive market, economy is an important consideration, but there is no doubt that this is an ideal technology, representing the development of CNC machining technology.
Toyota’s technical development tells us: good molds come from design; molds can also be produced by automated high-grade machines; high-tech application is the driving force of mold manufacturing technology development. We should look around the world, learn the advanced technology from different countries, and introduce it into our workshop, to elevate the global status of “Made In China”.
Immetech adheres to the approach of continuous upgrading; we are open to discussing the development trend of technology with people inside and outside the industry, strive to make use of more advanced and suitable equipment and software, and aim to provide better one-stop solution service to customers around the world.
We are very proud that Immetech has built over 80 sets of injection molds for Toyota in the past 10 years for our North America customers. These include mirror housing, outlet, bracket, car seat components, door panels, and more. We intend to keep learning from Toyota’s technology, and to continue upgrading our equipment and services, to build more tools for our valued customer around the world.