Automotive Light Plastic Molds

Product details

ADM Group excels at designing and building molds for headlights, taillights, fog lamps, reflectors, side markers, dome lamps, instrumentation, and other vehicle lighting.

Car light reflectors and bracket housings are our biggest specialties of auto lighting system.

Car taillight reflector parts in PC

Plastic reflector special structural characteristics need to pay attention to:

1) Part surface requirement is extremely high. Defects like spots, gate marks, or defects such as shrinkage depressions, weld marks and flash edges are all not allowed. And all the appearance features must to be made by machining, mostly are to be machined by CNC, no secondary processing like EDM.

So very accurate CNC machining is required, all must be done correctly in one time with very little space for reworking.

2) Plastic parts are to be electroplated. It has strict light distribution requirements by aluminum plated. Draft design of draft surface must be reasonable.

3) Shape of plastic parts is complex, surface smoothness is high, plastic parts are left and right mirror pieces and usually to be built into one mold.

4) To ensure reflector surface, reverse mold structure is required. Generally speaking: mold cavity is set in fixed mold, and core is set in movable mold. Since mirror plastic core is a multi-curved reflection and concentrating work surface, it requires a very low roughness, and it is absolutely impossible to set a push-out device such as a push rod, so mold must be inverted, that is protruding core (mirror working surface) is set in fixed mold, and concave cavity is set in movable mold

5) High precision requirements for plastic parts

Light distribution requirements of lamp mirror are extremely high, roughness of mold reflecting surface, processing and assembly precision are extremely high. In addition to mold side lock and guide post positioning, mold also needs to design mold mouth positioning to ensure three-level positioning of mold is reliable. Area of light distribution of mirror polyhedron is small, and it is impossible to carry out manual polishing. It is necessary to use a precision five-axis high-speed CNC machining machine, and spindle speed of machine tool reaches 20,000 rpm or more. Using advanced CAM technology and special tools, choose a reasonable processing technology, one-time processing in place. Cavity precision is required to be 0.01-0.02 mm, and cavity surface roughness is 0.05-0.10 μm.

Key points need to be followed when designing and building molds for auto reflectors:

1) Parting surface is smooth and has no sharp corners, no thin steel, wireless or dot sealant; surface sealant is constructed, and method of stretching, sweeping, meshing is used in parting, and parting is constructed according to shape of plastic part. Parting surface of lamp mold is extremely high, and surface of built surface is not allowed to wrinkle. Constructed parting surface can effectively guarantee CNC machining precision, does not require EDM clearing angle, and parting surface is not prone to burrs. High-speed machine is required for lamp mold splitting surface light knife, and spindle speed of machine tool is guaranteed to be at least 20,000 rpm per minute

2) Matching part between insert and movable mold, root of stop is designed with a suitable process to reverse R angle or avoid vacancy, which simplifies processing procedure, reduces processing time and improves processing efficiency.

3) Avoiding gap of parting surface: for example, if width of mold parting surface is 40MM, then fixed moving mold outside parting surface should avoid 1MM to effectively reduce processing time. Avoidance of parting surface refers not only to peripheral parting surface, but also to large-area parting surface. Special note: Width of mold parting surface includes exhaust groove. In large area of shelter, pressure block should be designed to ensure uniform force of lamp mold, avoid appearance of burrs during long-term production of lamp mold, and avoid air in perforated area. At the same time, vent hole should be designed in fixed or movable mold to facilitate discharge of compressed air when mold is closed.

4) Parting surface is constructed according to shape of plastic part, and plastic part is optimized when necessary. For medium and large molds, pressure plate groove is opened as much as possible to facilitate CNC machining. When designing parting surface, try to simplify mold manufacturing, smooth as principle, parting surface is made without thin steel, no sharp corner, and insertion angle is reasonable.

5) Split surface is smooth and flat. When UG splitting, it is forbidden to have many broken facets (easy to knives during CNC machining, and machining accuracy is reduced). Try to build parting surface with extended surface, mesh surface and sweep surface, or extend 10-20mm sealing surface first, and then make stretching surface and transition surface. Sealing surface is designed according to tonnage of injection molding machine and size of lamp mold.

Product Details

http://www.admmould.com/