Injection molding equipment and machinery is the backbone of the process and a variety of manufacturing operations. As injection molding can produce high product volumes and is highly automated, it requires proper maintenance of the tools to yield optimal results. If you’re looking for low-cost plastic injection molds you should make sure that your manufacturer has in place regular and efficient preventative maintenance, since it’s an essential part of the process. With molds that aren’t properly maintained, you risk getting final products that don't meet your specifications, cause extra downtime, and waste raw materials. Keep reading to learn more about proper maintenance of an injection mold.
What is the maintenance of injection molds?
Preventive maintenance allows manufacturers to identify and correct any problems before they become a serious risk to production. Here are some of the most important steps:
Basic checks before and after every production cycle
It’s necessary to thoroughly inspect the molds before beginning each cycle. Manufacturers should check the surface of the die to make sure it’s free of any contaminants. In case any debris is left inside, it can interfere with the clamps and cause the molten material to seep into the parting area during the process. It’s also important to inspect for any damage or anomalous marks on the mold’s surfaces.
Inspecting the final part from a completed cycle can provide useful information on the mold’s performance. For instance, if there’s excessive flash on the parting line, it can mean the core and cavity are not clamping properly.
Cleaning the mold cavity and core
Cleaning the mold after each cycle helps prevent materials buildup. It can be done with the mold on the bench or in the press. Bench cleaning is typically performed with other major maintenance tasks, while press cleaning follows each production cycle. Depending on the type of resin or ceramic powder used, the mold gets more or less dirty. Technicians wipe it down using a cotton cloth and a mild solvent or standard degreaser. Techniques such as dry ice blasting allow for a thorough cleaning without taking the mold out of its place.
When it’s time for more thorough maintenance and the molding tool is removed from the machine, it’s disassembled to clean each part separately. One of the most efficient methods is the ultrasonic bath which allows for a thorough cleaning of hard-to-reach areas such as mold vents and cooling channels. However, not all materials can undergo ultrasonic cleaning.
Checking sprues and runners
Inspecting the quality of sprues, runners, vents, and gates is essential for efficient production. Material build-up and wear are some of the most common failures that can cause the final part to stick to the tool. Wear is most likely to occur at the entry gate. Surface blemishes on the sprue or runner can impede the flow of molten material and also cause sticking.
In addition, scratches from earlier attempts to remove stuck material can further exacerbate the issue and cause it to stick more easily in the future.
Examining connectors and hardware
Checking pipe connectors, threads, and cooling water hoses is essential to make sure there are no leaks. Technicians remove fittings and pipes to clean any buildup. When the mold remains in place, they check if the bolts that connect it to the plates are properly torqued. If it’s removed, they should inspect the plates for rusting and warping. Any burrs or dents on the plates can damage the mold.
Hole threads tend to wear over time because of the softer metal of the platen, which is why they require periodical inspection. It’s recommended to use a torque wrench to prevent over-tensioning and damage.
