Views: 0 Author: Site Editor Publish Time: 2022-11-14 Origin: Site
Graphite Permanent Molding is a niche process used for casting zinc-aluminum alloy parts. The graphite permanent mold system offers a lower cost tooling alternative than die casting. Tooling is computer generated and fed directly to our high speed CNC Mills, where the graphite tool is cut. The speed in which graphite can be machined allows for rapid engineering changes, often in hours or days, as opposed to weeks or months like some alternative methods. These features allow the graphite system to exceed the potential of sand casting and to produce parts that rival those produced in a die-casting mold at a reasonable premium piece part cost.
Proper selection of the graphite grade is essential in the performance of the manufactured mold. Generally, given the relatively large porosity, extruded graphite grades are not recommended in the manufacturing of graphite molds requiring fine detail. There are certain high density extruded grades that could be a solution when budget restraints or low volumes dictate an economical solution. Most of the time, applications using fine detail graphite molds, utilize either molded or Isostatically pressed graphite grades. Both families of grades display high density and small particle size, perfectly suited for very high strength, very good finish and excellent life. Isostatically molded graphite has the best qualities for intricate mold designs and high volume runs.
Regardless of grade chosen, graphite is extremely stable. It will not warp, twist or check when molten metal is introduced. Parts can be cast with higher accuracy than sand or iron processes. Graphite can also be stored indefinitely without changing shape, rusting, oxidizing or deteriorating in any way.
Lower Tooling cost (Half of other casting methods)
Shorter Lead times
Greatly reduce secondary machining operations
Higher degree of dimensional accuracy and tolerances
Bearing quality eliminating the need for pressed in bushing
Advantages include:
Cast precision to +/-.005 which reduces secondary machining
Cast surface finish of 125 RMS or better
Tooling cost savings is as high as 50% to 75% over die castings and other cast methods
Excellent detailing and flatness
Tooling lead times of only 3-6 weeks
In conclusion, graphite molds can and do represent a viable, cost efficient solution. The engineering, design and manufacturing process, coupled with following the proper operating procedures can result in parts that meet or exceed customers expectations in both performance and service time.
