What is slide in plastic injection molds making?

The slide in injection mold, also known as the lateral core extraction mechanism, is commonly used in injection molds making. When there is an undercut on the side of the product that is inconsistent with the ejection direction, a lateral core extraction mechanism must be designed.

The principle is to first extract the buckle position and then eject the product, otherwise the product will be damaged. If there is a buckle position inside the product, due to space limitations, we will design an inclined ejector. Today we will share the types of sliders and design requirements.

What is the basic components of a slide in injection mold?

A conventional slider is composed of a slider seat – a slider insert – a pressure plate – a shovel – an inclined guide column – a limit screw – a wear-resistant sheet – a spring, and each component has a corresponding function.

When designing the slider, due to processing errors, in order to prevent interference between the shovel and the inclined guide column during movement, the shovel should be 2~3 degrees larger than the angle of the inclined guide column.

For the convenience of processing, the angle range of the inclined guide column is generally between 15~25 degrees. If the angle of the inclined guide column is 15 degrees, then the angle of the shovel should be 17 degrees.

Some positioning methods of slide in injection mold

1) Positioning with ball screws

The advantages are easy processing and simple operation; the disadvantage is that it is easy to damage. It is often used for small sliders in the X direction (horizontal) and sliders with large strokes. It can also help the slider to delay mold opening, because the ball will hold the slider against movement when the bevel is not working.

2) Spring and limit screw positioning

The advantages are easy processing and safe positioning. Commonly used for slides in the x and y directions and slides with small strokes. Calculation of springs: First of all, we need to know that the preload of the slide spring means that it still has preload when the mold is opened and the buckle is removed. Its purpose is to overcome the gravity of the slide through the elastic force generated by the preload to prevent it from moving back.

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(L stroke + 3~5 preload)/40%=L0(free length)

Spring hole depth: H = L0-preload-stroke

Detailed requirements for the design of the slider mechanism

1) The left and right sides of the slider seat must rub against the flat guide rail or L-shaped guide rail, and cannot rub against the mold base.

2) The wear-resistant sheet on the bottom of the slider seat must be 0.5mm higher than the slider groove, and the area of the wear-resistant sheet should be as large as possible.

3) When the slider seat goes deep into the inner mold, the wear-resistant sheet must also go deep into the inner mold and be made into a whole piece.

4) When the wear-resistant sheet comes out of the squeeze block, the wear-resistant sheet must be 0.5mm higher than the squeeze block.

5) When the mold base retains the slider seat, the wear-resistant sheet must be added to the mold base.