1. The Process of Silicone Key Mold Design and The Advantages and Disadvantages of Injection Method
Silicone keypad mold design and processing technology is divided into spray laser engraving, back printing, electroplating, etc.
When the silicone keypad product process is spray coating, there are two main glue feeding methods: direct glue feeding, bottom glue feeding, and point glue feeding. Recommended product: laser engraving silicone keypad (sprayed PU/sprayed feel)
When the product is solid, and the height is not greater than 1.5mm, the mold exit angle is not less than 1.5 degrees, and the product is not allowed to be filled with glue in other ways, the mold adopts the direct glue feeding method. The width of natural glue feeding is generally 2.50~3.00mm. The specific width of glue feeding depends on the size of the product. The thickness of glue feeding is generally 0.30~0.35mm, and the straight position must be 0.35~0.50mm to facilitate. For die cutting, the direction of the feet on the product frame should be opposite to the product's surface.
When the silicone keypad product is hollow, the height is less than 1.8mm, and the mold exit angle is not less than 1.5 degrees, the mold adopts the direct glue feeding method. The glue feeding width of natural glue feeding is generally 2.50-3.00mm, and the glue feeding thickness is generally 0.30-0.40mm. The specific glue feeding width depends on the size of the product, and the maximum straight position is 0.30mm to facilitate die cutting. To prevent the development from sticking to the front mold, the hollowed-out glue position in the rear mold of the product is generally not done. Draft and the direction of the feet on the product frame should be in the opposite direction to the product surface.
Advantages and disadvantages of direct glue feeding:
Advantages: Mold processing is easier to process, and injection molding production is more convenient for injection molding products.
Disadvantage: After the silicone keypad product is sprayed, cuts will be left when punching the nozzle, which may cause light leakage in the silicone keypad. If the stakes are not handled properly during die-cutting, the burrs produced are too large, which will affect the feel of the entire product after assembly. This is also the reason why silicone keypads rarely use direct glue injection.
When the silicone keypad product is solid, and the thickness is not less than 1.8mm, the draft angle is not less than 1.5 degrees, and the silicone keypad product allows the front and rear molds to be sandwiched and other methods of glue feeding are permitted, the mold adopts the bottom feeding method. Generally speaking, the back mold needs a glue position with a height of 0.30~0.50mm, and the rear mold position needs to be 0.05~0.08mm smaller than the glue position of the front mold on one side. The work of the glue in and out needs to be clear of the glue position, and the other glue positions need to be out of the front. The width of the mold and the bottom of the glue is generally 2.00~3.00mm; the length of the base is generally 0.25~0.30mm, and the direction of the column feet on the product frame should be in the opposite direction to the product surface.
The advantages and disadvantages of the bottom-mounted glue feeding method:
Advantages: The advantage of the bottom-mounted glue feeding method is that it is more conducive to the ejection of the mold and the punching of the product, and even if the nozzle burr is generated after the product is punched, it will not affect the assembly of the product and the feel of the finished product. The outcome after spraying There will be no light leakage.
Disadvantages: The length of the silicone keypad base will affect the glue-feeding speed of the product.
The dot-in glue method means the dots are directly placed on the product. The dot-in glue method is generally rarely used on main silicone keypad products. It is often used on higher-glue products or miscellaneous keys, especially on PC+TPU products. It is most widely used in two-color molds. The glue point of the product is usually made with a glue-reducing boss. This is to prevent the glue burr from leaving the glue when the glue is dropped, which will affect the product assembly or the feel of the finished product. The glue-reducing boss is The height of the table is generally 0.3~0.5mm, and the size depends on the overall size of the silicone keypad. Note: Glue-reducing bosses are generally arc-shaped and square-shaped.
Advantages and disadvantages of the point-in-glue method:
Advantages: The advantage of the point-in-glue method is that after the button product is injection molded, there is no need to punch the nozzle or perform subsequent processing.
Disadvantages: The point-in glue method may cause product shadowing on the surface of the corresponding silicone keypad product
during injection molding, especially the buttons with a textured surface effect. In addition, the glue injection pattern is difficult to control during injection molding, so it is generally not specified by the customer. Requirements YueHouDZSilicone Products manufacturer must take the initiative to adopt the direct glue dispensing method.
2. Printing on the back
Spray screen printing process silicone keypad.
For button products whose processing technology is back-printed, there is only one glue-feeding method, which is direct glue feeding. The glue inlet point of the front mold needs to be in a glue-reduction wave position. The glue-reduction depth is generally 0.5mm. This is to avoid scratching the screen due to burrs at the glue inlet during printing. The glue-reduction wave position can be made into an arc shape. And square.
For silicone keypads printed on the back, the draft angle should generally be no less than 1.5 degrees, the glue inlet width should generally be 2.5~3.5mm, and the glue outlet width should generally be 2~2.5mm. The position of the glue in and out is generally 0.~0.5mm straight to facilitate punching. The thickness of the adhesive in and out is generally 0.3~0.4mm. The specific value depends on the size and height of the button product and the frame. The direction of the foot pillars should be consistent with the surface direction of the button product.
For silicone keypad products whose processing technology is electroplating, the glue feeding methods are generally direct glue feeding and bottom glue feeding.
The glue-feeding characteristics of electroplated silicone keypad products are no different from those of spray keypad products. The size of the glue feeding point is generally Ф0.6~Ф0.8mm, and the slope of the glue column is generally 6-8. There is a mold in front of the button when it comes out. The point where the cotton enters the front mold must be glued to a glue position with a depth of 0.3~0.5mm. This is to prevent damage caused by dropping the surface when the product is modified in the future. to the glue inlet point.