Injection Molding, Injection Moulding Assembly for Plastic Injection Molds

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Plastic Injection Molding And It's Sub - Assembly Operations

Plastic injection molding is the primary process for manufacturing plastic parts. Plastic is known to be a very versatile and economical material that is used in many applications. Although the tooling is expensive, the cost per part is very low. Complex geometries are possible and limited only to mold manufacturability. Injection molding is a plastics manufacturing process where a liquid thermoplastic or thermo set is injected into a tool or die under pressure. It is suitable for very high volume production runs. Your computer monitor, mouse and keyboard, automobile parts and home appliances are injection molded plastics.

Injection molding involves taking plastic in the form of pellets or granules and heating this material until a melt is obtained. Then the melt is forced into a split-die chamber/mold where it is allowed to "cool" into the desired shape. The mold is then opened and the part is ejected, at which time the cycle is repeated. In spite of the relatively expensive tooling cost, injection molding remains the most popular manufacturing process for plastic materials in mass production, thanks to its low operational cost, high precision, and the flexibility to make parts with complex shapes.

Injection molding services include part design assistance, CAD, machined plastic prototypes, SLA models, prototype aluminum or soft steel tools, production molds, and production molding. This one-stop-plastic-parts capability provides design engineers with the best of all services to formulate fully functional and moldable components very fast. As the need for diversified plastics injection molding services for demanding tight tolerance water, air filtration, medical and consumer applications, the suppliers today offer design assistance, in-house mold construction, precision molding, insert molding, and complex assemblies. Materials include the most complex plastic granule from engineering grade to high performance grades with filled materials and foamed parts. Value-added services include product assembly, ultrasonic welding, spin welding, sonic stitching, pad printing, silk screen printing, hot stamping, heat sealing, etc.

Injection molding design

Plastic Injection Molding' s Mold design and Assembly

Using uniform wall thicknesses throughout the part which will minimize sinking, warping, residual stresses, and improve mold fill and cycle.
Use generous radius at all corners. The inside corner radius should be a minimum of one material thickness.
Use the least thickness compliant with the process, material, or product design requirements.
Using the least wall thickness for the process ensures rapid cooling, short cycle times, and minimum shot weight. All these result in the least possible part cost.
Design parts to facilitate easy withdrawal from the mold by providing draft (taper) in the direction of mold opening or closing.
Use ribs or gussets to improve part stiffness in bending. This avoids the use of thick section to achieve the same, thereby saving on part weight, material costs, and cycle time costs.

Many value added services like printing and hot stamping are generally done in the post injection molding process. These additional operations are only done after the molding process because they cannot be done during the molding process or at the molding machine. This is often because the post injection molding process is for example, placing the part into a CNC machining center after "aging" the part. Aging the part is used for the purpose of allowing the part to reach its maximum shrink properties so that in the machining process dimensions will not continue to move thereby rendering the part a reject after the machining process.

Plastic Injection Molding

Plastic Injection Molding to assembly operations

Screen printing : Screen printing is a printing technique that uses a woven mesh to support an ink-blocking stencil. The attached stencil forms open areas of mesh that transfer ink as a sharp-edged image onto a substrate. A roller or squeegee is moved across the screen stencil, forcing or pumping ink past the threads of the woven mesh in the open areas. Screen printing is also a stencil method of print making in which a design is imposed on a screen of silk or other fine mesh, with blank areas coated with an impermeable substance, and ink is forced through the mesh onto the printing surface. It is also known as "silk screening" or "serigraphy".
Hot-stamping : The advantages of hot stamping include increased productivity, multiple colors in one step, and a variety of available materials and finishes. The Hot Stamping, Heat Transfer Decoration of a wide array ofplastic parts and molds are possible due to the secondary production services available. Some of the assembly and sub-assembly services as well the following: flame treatment, hot stamping, point of sale packaging, labeling, and drilling.
Tempo printing : Tempo printing technique consists of transferring ink from the stereotype on an object by means of a silicone plug. This impression makes it possible to reproduce a logo or text on.
Spray painting : Spray Paint Injection Molding Technology is a sub-assembly operation on automotive industry, it's a low cost, novel in-mould painting system for injection molding that can be retrofitted to existing machine technology.
Ultrasonic welding : Principle benefits of ultrasonic welding include the ability to mold and assemble components with complex interiors, allow for designs not achievable in one shot and allow for final assemblies with internal components such as springs, chips, electronics and mechanical parts.

How does Poly Vison provide the services from injection mold design, injection molding production to assembly?