TOPSMOLD
Mold Design Service
The greatest number of plastic molds is made for injection molding,and in principle the problems are very similar to those encountered in pressure die casting of metals with one or two differences.the low viscosity of molten aluminium means that molds can be filled under pressure with this metal in a fraction of a second .the high viscosity of melted thermoplastic on the other hand means that mold filling times are very much slower,and pressures have to be much greater.Also metal process mold be water cooled to extract heat from the mold,whereas most plastic processing molds need not be cooled.
Like all molding processes,the quality and accuracy of the finished component depends largely upon the quality and accuracy of the mold cavity.A highly polished surface and adequate draft are necessary to give a good finish,and to assist ejection of the component.mold can be manufactured from cast iron or mold steel for short runs.ease hardened nickel chrome steel for medium production runs,and non-shrinking alloy die steel for extended runs. Cavities can be shaped by conventional machining techniques such as die sinking or speak erosion;or by hobbing .the last mentioned consists of forcing hardened ,male facsimile of the cavity called a hob into the being stress relieved and case hardened
The key Components of Mold Design
Gates
Gates are the openings at the end of the runners that direct the flow of molten plastic into the mold cavity.the gates of size and shape are depending on the part design and resin material. Design engineers must take into account a number of factors to determine gate types and locations to achieve optimum flow, fill pressure, cooling time, and dimensions/tolerance. It is important to locate gates where they won’t impact part performance or appearance (checking flow marks, shrinkage, warping by Autodesk mold flow ).
Draft
One aspect of mold design that it cannot be overlooked is the easy removal of the final product from the mold, with no damage to the surface of the part. it have to be by applying a draft angle, or taper, to the walls of the mold. The amount or degree of draft angle depends on several factors, including design of the part, material, depth of the mold cavity, surface finish, texture, pleasure from injection and amount of shrinkage. normally an angle of only a few degrees is applied to the side walls of the mold and creates enough space that the part can be easily removed when the mold is opened. Generally, the deeper the cavity, the more draft is required. Draft angles normally are from about 1 to 5 degrees.
Finish and texture
Mold cooling and part cooling are critical for effecting the surface finish. For example, a smooth surface finish on a 40% glass-filled resin depends on proper temperature control. The surface must be resin-rich with the fiber glass slightly deeper in the part, which requires a hotter mold—this also means it takes about ten percent longer to cool.
Molds can also be designed to apply a texture or pattern to the mold surface. there are difference textures include matte, gloss, graphics, grains, logos, and geometric patterns. Depending on the type, depth, and location of texture, draft may need to be adjusted to facilitate part ejection, which is determined during the mold design process.
Manufacturability and Lifecycle Costs
The main target of mold design and tooling is to create a product with high manufacturability—a high-quality process that is simple and efficient, long-lasting, easy to operate and maintain, so that it can meets customers specifications at the lowest possible cost. Fulfilling these expectations depends on designing the best tooling option for each customer’s needs.
To meet customer's needs must be made in the earliest design stages for decisions .we must be involved as early as possible to provide a realistic machining reviewed on product design, requested tolerances, tool design, selected materials, and associated costs. Taking this step up front is the best way to eliminate wasted effort and rework, which adds significant cost to the tooling budget. Part design and tool design are dependent on each other and therefore should be done concurrently whenever possible.
Please contact our sales to discuss your any questions:
sales@topsmold.com