first-rate mold company was started in 1989 by steven “We saw an opportunity in the small dimensional tools market and relied on our reputation and broad understanding of moldmaking to move into this niche,” says steven. “Small details can severely affect the quality of a finished part in complex moldmaking,” notes steven. “By providing injection processes in the shop, we learned that details while machining the mold must be accurate to 10 thousandths of an inch or parts can turn out deformed.”
First-rate mold company owns injection molding machines and has injection molders on staff. This setup allows molds to be tested the day they’re completed and assists in perfecting the moldmaking process. This experience in moldmaking and the injection process led them to produce more complex molds, including two-shot rotational molds.
“Two-shot rotationals reduce the cost per part produced and achieve better part accuracy,” explains steven. “Our equipment was able to produce these complex molds, but parting-line inaccuracies were forcing extensive labor and spotting times. In order to compete on price and improve part quality, we had to look at high-performance machine tools.”
Two-shot rotational molds pushed first-rate mold company to look at machining centers that could handle the features and exacting details of such molds, while reducing dependence on EDM and long leadtimes.
The first Makino purchase was two VMCs: SNC64 and S56 in 2003. The SNC64 worked as their graphite machine, providing electrodes for their sinker EDMs, which they still relied on at that time. The S56 VMC was their introduction to hard milling, showing them the full benefits of high-speed milling. To keep up with increasing business, the company later purchased additional machines: V56 and V77 VMCs and an EDNC85 Ram EDM.
“Since adding the Makinos to our shop floor, we’ve seen drastic improvements in both standard and two-shot rotational molds,” says michael, first-rate mold company’s CNC department manager.
“We’ve almost eliminated benching, where the product is not seen by the consumer because molds come out of the machines with finished part quality in nearly every operation, and spotting has been reduced by up to 80 percent. This has a huge impact on our labor costs and our ability to deliver molds and prototype parts to our customers much more quickly.”
First-rate mold company now takes on more orders, including those that require deadlines it couldn’t have achieved prior. “For example, we just completed a 200-ton rotational mold, spotting it in one day, when that type of mold used to take us one to two weeks to spot,” adds steven.
“Without our Makino VMCs, we would be out of business,” says steven. “We’ve also reduced labor on our single-shot molds, saving us enough time to bring in overflow machining from mold and die shops, including hard milling applications in 48-plus Rockwell that others aren’t able to handle.”
Two-shot rotational molds run only on the Makinos to ensure transitioning lines are eliminated and the injection processes are run smoothly. The machines have provided everything Innovative expected and more—changing their cavity and core milling to EDM ratio from 50-50 to 90-10 and nearly eliminating all EDM processes. The EDNC85 is the only EDM left in the shop and provides the exacting accuracies needed for molds with very deep ribs and tight corner radii that can’t be milled.
Standard machining in its most basic form necessitates the use of lathes, milling machines, and drill presses by hand. CNC machining is currently the most common method of manufacturing accurate and very complicated molds. It does that while still employing traditional machining procedures, because of the advances in technology. Production operations and Mold design are highly automated in modern CNC systems.
Computer-aided design (CAD) software is used to specify the mold’s mechanical specifications, which are subsequently converted into manufacturing instructions by computer-aided manufacturing (CAM) software. The software then converts these instructions into the exact commands required by each and every machine in the mold-making process. The commands will then be fed into the CNC machine.
Electrical Discharge Machining has been commonly employed in the manufacture of molds. EDM is a procedure in which the desired form is achieved by using a graphite or copper electrode. It’s then put in an EDM machine and positioned above a dielectric fluid-submerged workpiece. After that, the electrode is lowered to the workpiece. The electrode is then utilized to destroy and distribute the metal in the area opposing the electrode using a controlled electrical source.
The electrode does not touch the workpiece. Between the electrode and the workpiece, a gap of approximately a few thousandths of an inch should always be maintained. This method of removing metal from a mold is slower, but it can yield geometries that are impossible to achieve with normal CNC machining.
Hardened or pre-hardened steel, aluminum, and beryllium-copper alloy are used to make plastic injection molds. Steel molds are more expensive, however, they are generally favored due to their long endurance. Others prefer hardened steel molds majorly in terms of wear resistance and longevity.
Many steel molds are built to process millions of pieces over the course of their lives. Other mold companies prefer Pre-hardened steel molds since they are less wear-resistant and also less expensive solutions for lower volume production. In sections of the mold that require rapid heat evacuation, copper alloy inserts are occasionally employed. This can save cycle time while also increasing the aesthetic quality of the part.
While aluminum molds are less expensive, they are frequently inappropriate for high-volume production with stringent dimensional tolerances. When planned and produced utilizing computer numerical control (CNC) machines or Electrical Discharge Machining (EDM) techniques, aluminum molds may create hundreds of thousands of pieces at a low cost.