Plastic LED Lens Injection Molding Production Manufacturer

LED Lens Manufacturer Full-service: Lens Design Services, Precision Mold Building Services, Injection Molding Mass Production.
Material: Japan optical grade transparent plastic PC 1250Z, imported S136H super mirror A grade plastic mold steel.
Quantity: A series of LED street light lens products as many as 20 models, more than 50 sets of moulds, and the output of plastic lenses is as high as 2 million.
LED light lenses injection molding service

Experienced LED Lens Manufacturer for Street Light

This is an example of one client RD company we have worked with for many years. RD Company undertook the local government’s infrastructure improvement project and provided new energy-saving LED street lights. In 2013 they were looking for a professional led lens manufacturer. That was the first time we assisted this client in improving their first LED lens project.
LED Lens 3D drawings
From the sectional view of the bulb in the 3D product image, we can see that the original design of the lens is a solid bulge with a flat bottom. And the maximum thickness has reached 9mm. This is obviously a first-generation lens with a simple structure. It seems that the previously led lens manufacturer didn’t understand enough about optical refraction. Such a product structure is a big challenge for the injection molding process.

In the past, the customer has made molds in other optical lens factories, but unfortunately, they could not inject qualified LED lenses anyway. When the RD client showed us the product he got, he directly described it as “horrible”, and he was very worried that he would lose the project if it went on like this.

Defects in injection molding LED lenses
In the above picture, it is obvious that the molten plastic has serious bond line problems after molding and cooling. And the position of these bond lines happens to appear on the most important sphere, which is obviously unacceptable. The reason for this undesirable phenomenon is the unreasonable design of the injection mold and the defective analysis of the mold flow, which leads to poor control of the bonding line.

RD client visited our factory for the first time in August 2013. At that time, the “peanut rice” bulb structure has become popular in China’s LED street lamp lens industry. So in face-to-face communication with them, we suggest that they improve the design of this raised bulb. The “peanut” structure can not only reduce the weight of the product for lower manufacturing costs but also improve the optical effect. The new design is more conducive to injection molding of high-quality plastic LED lenses.

The client greatly appreciated our design and advice and hoped that we could salvage his first lens project and apply the new structure to future lens designs. Based on our rich experience in plastic led lens injection molding production, our engineers believe that we can completely improve the bonding line problem in the injection molding process according to the customer’s original spherical structure. The customer immediately decided to let us help remanufacture the mold for the first street light lens. After 30 days, we completed the mold manufacturing of this 350*220mm lens as scheduled. We provide beautiful T1 samples to customers. Of course, we got a thumbs up.

LED lens manufactured in sungmould
Our mold designers fully demonstrate their expertise in mold flow analysis and mold design. For example, in the selection of the injection feeding method, we agree that dispensing gate can make the molten plastic raw material fill the cavity more reasonably. But how many gates can be used to better avoid the problem of bonding lines in the molding process? We preset 2, 3 and 5 gates, then fully evaluate the impact of different schemes, and reserve the structure of the glue inlet during the mold manufacturing process. This makes it possible to change the number and distribution of gates according to actual needs. After comparison, the final choice is 2 glue inlets.

After the completion of the first spherical LED lens, starting from the second LED street light lens project, RD customers have adopted the “peanut rice” structure we suggested to him instead of the original bulb structure.

LED lenses injection molding service
making LED lens
While helping the customer to solve the structural design, we also help him solve the problem of light distribution of the lens. We fully communicate with customers the optical effects to be achieved, such as the suspension height of the lamps, the area of ​​the floor, the horizontal and vertical illuminance, the uniformity of the illuminance, the color temperature and the glare index GR, etc. Then our designers use professional optical light distribution software to assist customers in completing the crucial light distribution work. All of these are what a professional led lens manufacturer should do.
LED Lens industry
For these larger size LED street light lenses, there is generally no need to manufacture prototypes. The traditional process of making prototypes such as CNC machining and vacuum casting cannot make qualified lens samples. Customers generally directly custom high-precision plastic injection molds for mass production. Therefore, the light distribution process before mold making is particularly important. Only when the computer-simulated optical illumination effect meets the customer’s requirements, the design can be determined to be qualified.

So far, RD has customized the production of more than 20 “peanut rice” lenses. We have shipped more than two million units to them. This kind of “peanut rice” street light lens makes the customer’s products very competitive. We are very happy that our work is valuable.

street light lens
LED street light lens

Manufacturing Review of LED street light lens

Mold Design

When designing the mold, we need to consider the raw material filling process of injection molding, and then do DFM mold flow analysis to design the most reasonable injection feeding method and ejection scheme. Fully consider the flow direction of the molten plastic, and try to avoid bonding lines appearing in important structures, such as the precise optical parts of the bulb. If necessary, redundant filling pits can be designed to achieve the purpose of adjusting the bonding line.

Designing a cooling system requires incorporating mold flow analysis. The designer carefully considers the influence of cooling on the flow of molten plastic, abandons the conventional “#” cooling system thinking, avoids structures such as thimbles, and designs a reasonable cooling water flow route to achieve a reasonable cooling effect.

Selection of cold runner and hot runner. For LED street light lens products, the answer given by our experience is that a hot runner is an unnecessary option. We have done many street light lens molds with a cold runner structure. This not only helps customers save tooling costs but also saves tooling time. The direct injection method also facilitates us to adjust the injection molding process and obtain qualified test samples faster.

Mold Building

It is not good to use regular die steel or regular CNC machining to make lens molds. They must be made of S136H mold steel with the same A-grade quality, using ultra-high-speed and high-precision mechanical engraving, and using Sodick mirror EDM to process the subtle structure, and then super-mirror polishing, and finally produce a qualified precision mold core.

Since the precision control of the mold processing process is very strict, the later mold assembly and adaptation are relatively easy. Our mold engineers only need to pay attention to the proper alignment of the parting surfaces after the mold core and mold base are assembled.

Injection production

As an experienced LED Lens Manufacturer,we deeply understand the adjustment of injection molding conditions directly affects the quality control of LED lenses. The injection molding machine should choose a special screw for PC raw materials. If the injection molding machine needs to be used for mass production of LED street light lenses, our company recommends this injection molding machine to inject colored plastics. The flexible opinion is that when necessary, we can disassemble the screw of the injection molding machine and do polishing and electroplating. Injection molding of this transparent plastic material for lenses is also more difficult than ordinary PC, PP and ABS.

Selection and control of temperature and pressure are also important factors. The general LED street light lens is rectangular. We have manufactured lenses longer than 420mm. The longer the length of the lens, the easier the problem of product deformation after injection molding occurs. In order to avoid the problem of appearance deformation, the designer should design some reasonable bone support structures as much as possible when designing the product, and also consider the pre-deformation and set the molding conditions (pressure, holding pressure, cooling time, etc.) It needs to be adjusted based on past experience. The rich experience in injection molding of this transparent PC material helps us to manufacture high-quality street light lenses better and more efficiently.

Optical Effect Verification of LED Street Light Lens Manufacturing

The molding of the lens is precision injection molding. The lens product obtained after the molten plastic is cooled in the mold needs to be strictly checked for dimensions. Different from conventional plastic products, the dimensions and tolerances of lenses are all at the micro-level. We have a professional light distribution performance testing system to check the real effect of the lens.
light distribution performance testing system

Optical grade PC1250Z plastic raw material as the raw material of LED lens

Finally, we would like to share with you the characteristics of this optical grade PC1250Z plastic material. This material is the best result our optical engineers have come up with after dozens of tests. It has high transparency, moderate molding shrinkage, and the manufactured “peanut rice” structure is in good agreement with the results obtained by light distribution analysis. Its weather resistance is also better than ordinary PC, and it can get a longer and more stable life when used in outdoor LED street lights. Many of our customers used TAIWAN CHIMEI PC before, and they all agreed with this PC1250Z after our suggestion and obtained better quality lens products. If you are still hesitating about what plastic raw materials to use to make your LED street light lens, I hope our experience will be helpful to you.

Your One-stop Lens Supplier for Customization

Sungmould is a leading provider of on-demand manufacturing services in China. Precision plastic tooling and injection molding are our core, while prototyping and CNC machining can better support the needs of low volume production. We provide plastic injection molding and contract manufacturing in home appliances, consumer goods, electronics, LED lenses, industrial products, automotive, and energy markets.

When you choose Sungmould, you get a professional partner through the entire production cycle. Timely, professional, and effective communication is always with you, taking your product from concept or drawing to reality.

Hope you enjoyed this case study overview and may have gained some insights that can help you with your next project.
If you have an LED lens to design and manufacture, or need to custom a plastic product, we are always ready to provide a free quote and project review.

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