Putting an excellent manufacturing process in place is a critical requirement that is expected, especially for a complex manufacturing project such as mold manufacturing. Considering the many moving parts involved in mold manufacturing, including fabrication, inspection, and testing, understanding the nitty-gritty of each process will ensure high-quality mold production.
However, using highly precise methods and tools like CNC machining afforded by technological advancement is an advantage that manufacturers and mold design professionals can tap into to make the process very effective. In this guide, you’ll discover the various aspects of the mold manufacturing process and how to make each step more efficient to get the best quality mold for your projects.
II. Mold Fabrication
A major aspect of mold manufacturing is the mold fabrication stage, a thorough understanding of which can help manufacturers and mold designers optimize its production. To start with, the fabrication stage is further divided into three sub-sections, including mold design, production, and post-production stages. The mold design stage includes the evaluation of expected stresses and pressure on the mold, material selection, and shape dimensioning. This stage is typically the forte of the mold design engineer in collaboration with the product specialist to ensure they both develop a buildable and high-quality mold. The production stage is the main fabrication stage, where the fabrication specialist ensures the design is implemented. Lastly, the post-production stage provides finishing touches on the fabricated molds, including removal and appropriate stacking of the molds in the designated area. Again, during the design stage, a suitable material fit to withstand the pressure and temperature range required for mold production is specified by the design engineer. Some commonly suitable materials include metals and alloys like brass, bronze, aluminum, and steel. Also, thermosetting plastics and thermoplastics are ideal for small-scale and complex geometry mold production. Other materials like carbon fiber, fiberglass, and other composite materials are a recent addition to the list of suitable materials for mold production, considering their lightweight and high strength advantage. Other considerations during the mold fabrication process include the material properties like its composition, strength, and hardness, which indicates its durability after the production process. Also, the fabrication process, which can be welding, casting, or CNC machining, will significantly depend on the type of mold and the project requirements. The mold production scale and the mold shape’s complexity also determine the mold’s fabrication method.
III. Mold Inspection and Testing
Fabrication is one step in the whole mold manufacturing process. However, once the mold has been produced, the next step is to confirm its conformance to design specifications using an inspection checklist. You’ll also need to conduct standard tests for the molds to ensure they meet quality requirements as prescribed by the design engineer, following applicable industry codes and standards. However, the inspection is done in phases which include functional, dimensional, visual, and surface inspection.
The first point of call for inspection and testing often starts with a basic visual inspection. This entails checking for surface defects, including deformation, cracks, irregular elongation, and other defects easily detectable solely from sight.
After affirming that there are no visible defects, the next thing is to carry out a dimensional inspection which requires measuring the dimensions of the mold to ensure it conforms to the designer’s provision. This dimensional inspection is a more rigorous form of visual inspection since it uses measuring tools like tapes, veneer calipers, and micrometer gauges.
The functional inspection then follows the dimensional checks to ensure the mold conforms to the operational requirements specified at the mold design stage. It also helps manufacturers evaluate the performance of the molds given the parameters expected when the mold is in use, for instance, in rapid prototyping.
Lastly, manufacturers often inspect the mold’s surface finish using optical instruments that expose any surface imperfections on the mold. Sometimes a mold’s surface finish can be the most critical consideration depending on the peculiarity of the project and the intended use of the mold.
Tests are also carried out primarily to ascertain the presence of defects hidden from eyesight, including thin cracks that can amplify the intensity of stresses on the mold, resulting in failure. Non-destructive tests (NDTs) are common with molds which require special tools, endoscopes, ultrasonic transducers, surface roughness testers, and coordinate measuring machines (CMM). These tools are mostly expensive but deliver highly accurate and precise results in detecting hidden faults in the manufactured molds often used for plastic injection molding.
In conclusion, understanding the steps involved in mold manufacturing and their impact on the quality of the mold is essential for all mold manufacturing professionals. From the fabrication processes to the inspection and testing of molds, every step is critical and adds value to the quality of the product.
Industries such as automotive and aviation rely heavily on molds to manufacture critical components and benefit immensely when their personnel understands these manufacturing processes.
Also, considering that technology is speedily progressing, with several innovative manufacturing solutions coming up almost daily, it is only natural for mold manufacturing to continue to improve. Consequently, the level of manufacturing error will reduce with the invention of more accurate mold manufacturing tools and equipment.