With local firms facing increased global competition many face increased pressures to lower production costs. Just-in-time manufacturing has proven popular as it centres on the elimination of waste in its broadest sense. Manufacturers strive to lower stock levels and product defects.
Traditional tooling while presenting economies of scale in terms of component cost often proves costly for high value low volume product manufacturers as they are forced to hold large quantities of stock for low value components. For manufacturers involved in the production of new designs the identification of production errors can also prove costly once tooling has begun, and initial stock levels received for production components. Adjustments to the design may lead to wasted stock along with the additional costs associated with setting up a new tool for the tooling process.
In an effort to avoid these potentially costly production pitfalls a number of manufacturers have turned to vacuum casting, allowing them source low volumes of production components.
The Vacuum Casting Process is used to create plastic or rubber components for silicone moulds. Parts produced using this process are precise, dimensionally accurate replicas of the master pattern with all profiles and textures faithfully reproduced. The process involves the following steps
- A master pattern is created using 3D CAD data and any of the available Rapid Prototyping processes, typically SLA due to the high quality part finish that can be achieved using this process. Post production finishing is then carried out to achieve the required part finish.
- A casting gate is fitted to the master pattern which is then placed upon the parting line and suspended in a mould casting frame. Silicone rubber is mixed, de-aerated and then poured into the mould casting frame, where it will flow around the master pattern.
- The mould is then cured within a heating chamber. Once set the silicone mould is cut along the parting line and the master pattern removed.
- Urethane resin is then measured, and where colour has been specified a dye added. A casting funnel is placed and the mould is sealed closed.
- The resin is then mixed and poured under vacuum by computer controlled equipment, to avoid any air pockets or voids.
- Once the resin is cast, the mould is then moved to the heating chamber where it will remain for approximately two to four hours, allowing the urethane resin to cure. After hardening the casting is removed from the mould.
- The gate and risers are removed and any post production painting or plating completed to produce and exact copy of the master pattern. Each mould can be used to produce between 15-30 castings.
Brandon Medical, a high value low volume manufacturer of medical lighting units turned to Vacuum Casting when they sought to reduce stock holdings for low value components of their HD LED Quasar lighting system. While wishing to lower their inventory levels Brandon Medical were conscious of meeting customer lead times and quality expectations. Vacuum Casting presented the ideal solution.
Using a local Rapid Prototyping bureau, Brandon Medical were able to source cost effective high quality production parts within days, eliminating expensive tooling costs and the need to hold large volumes of stock.
Post time: 04-24-2017