【 Liquid silicone rubber】 Technology Analysis of the liquid silicone watch band

LSR wristband (hereinafter referred to as wristband) is now the new favorite of watches and other wearable devices, and it is widely used. Soft and comfortable, easy to clean, not easy to scratch and so on.

The strap is non-toxic and tasteless, flexible and comfortable, tear resistant, anti-oxidation, with strong waterproof and corrosion resistance, long service life.

Second, the structural characteristics of LSR strap are difficult

The product structure is complex, the hole is more, the sealing position is more, the sealing glue of the second shot silicone and the first shot hard glue is complex, and the appearance requirements are high, the silicone fluidity is good, it is not easy to seal, and the product is easy to run rough.

Third, LSR strap mold characteristics

The product structure is complex, more holes are broken, more sealing positions, and the overall dimensional accuracy requirements of the mold and the overall assembly requirements of the mold are very high. Our mold mainly adopts the method of cold flow channel injection, and the number of holes is reasonably set according to the actual dosage demand.

Fourth, LSR strap common problem analysis and solutions

1. Product size out of whack:

Analysis: Mold design defects, mold processing accuracy is not enough, mold frame accuracy is not enough, and size control is not in place.

Scheme:

(1) In mold design, the key dimensions need to be marked clearly, the tolerance is reasonable, and each process needs to be strictly measured and controlled in place for the key dimensions and assembly dimensions, from parts processing to assembly assembly;

(2) The accuracy of the mold frame should also ensure the opening accuracy and positioning accuracy;

(3) Grasp the standard shrinkage rate according to the physical property table of the selected silica gel material.

2. Raw edges of the product

Analysis: The structure of the silicone strap is complex, the parting surface is more, the LSR itself has good fluidity, the overflow edge value is small, the parting surface, the entering place, etc., is easy to produce rough edges, and the overall processing accuracy of the mold and the coordination accuracy of the sealing position are higher.

Scheme:

(1) The mold design needs to be reasonable and rigorous, comprehensively evaluate the characteristics of LSR material, and define the dimensional tolerance assembly requirements of each workpiece;

(2) The matching dimension accuracy of each insert and die should be controlled in place;

(3) Need to design a reasonable edge tearing groove structure;

(4) a reasonable prepressure value of the mold and the hard glue.

3. Bad exhaust problem

Analysis: mold exhaust mode design is not reasonable, forming parameters are not reasonable.

Scheme:

(1) The vacuum mechanism must be designed if the mold structure allows;

(2) The mold flow analysis needs to predict the trapped gas position of the binding line in advance, and design a reasonable and effective exhaust;

(3) the finish of the parting surface and the closing of the mold should meet the requirements;

(4) The injection speed, pressure and mold forming temperature should be set reasonably;

(5) A/B rubber mixing is not uniform, resulting in a large gas content of the material itself.

4. Not easy to tear edges

Analysis: The design of edge tearing groove is unreasonable, and the edge tearing edge is worn.

Scheme:

(1) A reasonably designed edge ripping slot;

(2) Regular mold maintenance to prevent knife damage.

5. Easy to stain appearance

Analysis: The surface of the silicone watch band is easy to generate static electricity, easy to absorb dirt and dust.

Scheme:

(1) The production operation needs to control the dirt caused by environmental factors in the process;

(2) Production needs to wear clean gloves;

(3) Prevent the product from absorbing dust by static electricity.

Guangzhou S-guangyu Machinery & Equipment Co.,Ltd is a professional liquid silicone rubber(LSR) Injection molding machine manufacturers in China since 2010.We have got more than one hundred patents and serve for more than thousands of customers .if you want to learn more about our machines,please visit our web www.lsrexpert-better.com or contact us:86-13902294163.