CHOOSE THE RIGHT GREASE
In my job I have had to address cases of running hours of scrap after preventive maintenance—that is, when the mold is completely disassembled, cleaned, and greased with new lubricants. I have found that some greases are more prone to bleeding if not applied properly, and others do not hold up well in high temperatures with high mechanical friction. I have tried out numerous greases on the market, and not one covers all situations and applications. But it is critical to find the right grease for your application.
It is also important to make sure your components are designed properly and use proper coatings and hardnesses to reduce failures. It is not always the lubricant at the root cause of mechanical failures. In some cases, greaseless tools are necessary and can achieve good maintenance results if properly designed and coated. For high-volume tools, I typically specify 100,000 cycles between PMs for most materials; but with higher-temperature and glass-filled materials, I set the spec at 50,000 cycles. And there are always cases where those cycle counts are too high.
MAINTAINING MOLDS IN THE PRESS
You should also have a setup procedure to maintaining the parting-line shutoffs, vents, cavities, and wear surfaces while the mold is in the press. This will vary from tool to tool and the material being molded. For example, with gassy materials, vents and parting lines will need to be cleaned more often. If vents continually need to be cleaned, I would evaluate the venting itself.
The article comes from China injection mold manufacturer - Mold Best Assurance Company Limited, website is www.mbamoldanddesign.com
