Locating Block

Because there is a gap between the guide pin and the guide bush, it is necessary to use higher positioning parts to ensure accurate mold clamping.

• If the corresponding positions of the cavity (fixed mold insert) and core (movable mold insert) are not completely coincident, the core insert and the side core slider and other parts will collide and cause damage or abnormal wear. Sometimes It will also cause the size difference of the formed product and produce burrs.
• Positioning the corresponding positions of the cavity (fixed mold insert) and core (movable mold insert) to prevent their misalignment can avoid such undesirable phenomena.
• Connectors and electronic component molds use a large number of small and precise cores with narrow spacing. In order to avoid collisions between cores, precise positioning is required.
• The side locating block components are installed on the side surface of the mold, which is extremely convenient for loading and unloading, and the mounting holes (grooves) on the template are easy to process.

Because the fit gap is extremely small, please use precision pole guide posts.

Usually a precision injection mold is composed of seven systems, and the positioning system is one of the important systems, also called the guiding system. Unreasonable positioning system design will greatly reduce the life of the mold, resulting in mold damage, product misalignment, and dimensional instability.

1. The first stage of mold positioning

First look at the first repositioning. The initial positioning of the mold is also done by the guide pin and guide bush on the mold base. The fit between the guide pin and the guide bush is a clearance fit. Take the MISUMI precision guide pin and guide bush, with a diameter of 25mm as an example, the fit clearance is about 0.02-0.03mm. In precision molds, the accuracy is relatively poor. The guide pins and bushings of the molds in production are unavoidable even if they are lubricated. In some poorly managed companies, the guides are not lubricated in time, and the situation is very dry. It is common and wears more severely. Some people will ask why the matching gap is small, it is not impossible to do it, or it can’t be done. If the gap is too small, it will be easy to burn out. The mold guide pillar is mainly the primary positioning of the entire mold. The positioning of the front and rear molds is completed by the cooperation of the guide pillars and the guide bush of the front and rear molds. The positioning accuracy depends on the machining accuracy of the mold blank hole and the dimensional accuracy of the guide pin and guide sleeve. Inaccurate machining of the mold blank hole will cause the guide pin to burn and strain. The guide post is also the main part that bears the weight of the mold blank. Pay attention to its strength. If the guide pin is too long or too weak, it will cause inaccurate positioning and burn and strain problems of the guide pin

2. The second stage of mold positioning

The second repositioning is usually completed by locating block, round interlocks, etc. on the mold base. The matching accuracy is relatively high at 0.01mm, which can effectively compensate the positioning error of the guide pin and guide bush, and can also avoid the lifting error of the mold on the machine. The mold lock is the secondary positioning of the mold, which is the precise positioning of the front and rear mold blanks. The positioning accuracy of the locating block is much higher than that of the guide pin. The matching grooves of the locating block on the mold base are processed to the exact position as far as possible to ensure the matching accuracy of the front and rear mold bases. The mold lock material adopts heat-treated material or wear-resistant beryllium copper and graphite material, and there should be oil groove lubrication on the friction surface of the locating block. The mold lock can effectively protect the weak inserting surface on the mold core.

3. The third stage of mold positioning

The third repositioning refers to the positioning of Positioning Angle. With the development of CNC technology, the practice of Positioning Angle is more and more accepted by everyone. Now more and more mold companies adopt Positioning Angle design when designing molds. The purpose of Positioning angle is to accurately position the moving and fixed mold core. The angle of Positioning angle should be more than 1° smaller than the mold core insertion angle, and the height is more than 2mm. The three-level positioning refers to the precise positioning of the Positioning angle designed on the mold core, which mainly protects the precise positioning of the mold inserting surface.

Positioning angle of the mold core is the precise positioning of the front and rear mold cores. It is the main positioning mechanism that effectively protects the upper inserting surface of the mold core, and also bears the lateral pressure of the injection molding. Positioning angle is generally designed for angle insertion, and the angle should be 0.5-1 degree smaller than the minimum insertion angle on the mold core and the appearance of the grain surface to ensure that the mold core is effectively protected and effectively prevented during the mold opening and closing process. Textured noodles and flowers. Positioning angle is tighter than the mold core when processing and matching molds. Mold factories with precision processing strength try to set reasonable processing tolerances separately, and try to minimize manual matching to ensure the accuracy of matching. This is for precision molds. especially important. The height of the positioning angle is designed to be 1-2mm higher than the highest surface of the mold core as much as possible, which can effectively protect the mold core surface.

The three-level positioning (guide pin and guide bush, locating block, Positioning angle) of the injection mold requires more precise first-level positioning than the first-level positioning. I have analyzed the three-level positioning (guide pin and guide bush, mold lock, Positioning angle) problem of the mold from the perspective of precision molds. In fact, regardless of the precision mold, I suggest to do a good job in the three-level positioning of the mold (guide pin and guide). Bush, locating block, Positioning angle), this is a necessary design to ensure the quality of injection molded products and improve the service life of the mold, and we must pay attention to it. Unless your mold does not have any inserting surface and appearance texture surface, you can omit part of the positioning design, and you must design the three-level positioning of the mold (guide pin and guide bush, locating block, Positioning angle), and do well in accuracy.

FAQ:

1. Question: What is the difference between locating block and side lock in plastic molds?

Answer: The locating block has a wide range, including side lock, top lock, interlock and so on. They are in different positions, but the functions are mostly the same. They are why the upper and lower molds can be closed without deviation; or according to the plan Move in the direction. Side lock mainly refers to the positioning device installed on the side of the mold.

2. Question: What injection mold needs a side locating block? Is the positioning accuracy of the four guide pins still not enough?

Answer: Any part will have tolerances. The longer the guide pin, the greater the deformation, and the greater the friction stroke with the guide bush. Therefore, as the number of mold openings increases, the wear guide pin and guide bush have almost no accuracy at all. As the name suggests, it’s just a guide. At this time, the role of the mold lock is revealed. It can play a role of precise guidance and positioning at the last 15-20mm of the clamping stroke. The locating block also has a name called “guide pin assistant” for this reason;

3. What are the materials used in the locating block?

Most of our locating blocks use mold steel (1.2510) with a hardness of HRC55-58. They can also be produced with SKD11 materials according to customer needs.

4. How accurate is the locating block?

The locating block mainly relies on the accuracy of the positioning surface to achieve positioning. Our standard accuracy is 0.01mm, but the accuracy of the ultra-precision level is between 0.003mm-0.005mm.

5. What are the main aspects of evaluating the performance of locating block?

First of all: a good locating block must first have better materials, they must be hard enough and not easy to wear. THREEUP’s locating block uses high-quality raw materials from well-known companies to ensure that the raw materials of the products are good enough and will not use false low-grade materials to pretend to be.

Secondly: the heat treatment of the locating block is very important. The mold lock after heat treatment is more hard and wear-resistant. How to choose a heat treatment partner with stable and reliable quality is important. THREEUP’s heat treatment is the most famous heat treatment manufacturer in the local area, which can guarantee the quality of the locating block

Finally: the accuracy of the locating block is very important. Only skilled workers, excellent grinder equipment, and too much good work can produce qualified products. Of course, the work of a responsible quality department is also very important. Fortunately, THREEUP did this.

6. Why is the color of some locating blocks black or gold?

The black mold lock is made of DLC coating. DLC coating is also called diamond-like carbon coating. It is an oil-free and self-lubricating coating with high hardness and ultra-low friction coefficient. It reduces the friction between mold lock, There by increasing the service life of the locating block. The golden one is made of a titanium coating (Tin), which has the advantage of improving the wear resistance of the mold lock, preventing the locating block from jamming, and reducing the sliding friction coefficient of the locating block, so that the locating block fits more smoothly.

7. There are many types of locating block, how do I choose?

There are indeed many types of mold lock. How to choose it depends on the following points.

First: customer requirements. Generally speaking, European customers are accustomed to using STRACK specifications and HASCO specifications, Japanese and Southeast Asian customers love to use MISUMI specifications, and American customers love to use DME mold lock. This is not only a question of habit, but the important thing is that it is easier for customers to find the same type in the local area. Replace the locating block.

Second: the structure of the mold. The commonly used mold locating block is to install the locating block on the periphery of the mold. In this case, a side lock is required. However, sometimes due to the limited structure of the mold and the influence of waterways around the mold, the internal style is also selected. In this case, you can choose top lock and interlock. In some molds, because of the high temperature, in order to avoid the influence of expansion, taper models, such as tapered locks, are used.

Third: the accuracy of the product. Our locating block has ordinary models and high-precision models to choose from. If some high-precision electronic products are recommended to use high-precision locating blocks, and molds that do not require strict product accuracy can use ordinary models, their The price will be more advantageous than high-precision products.

8. What is special about the taper locating block?

The taper locating block component can absorb the thermal expansion of the template when the mold temperature is high and ensure the correct positioning function.

Some high-temperature molds, if common l mold lock are used, sometimes cannot fully absorb thermal expansion. In this way, due to uneven heating, the locating block may be inaccurately positioned due to different expansions, so that the mold lock cannot be completely matched.

At this time, if the taper locating block can be used to set the direction of the groove parallel to the direction of thermal expansion, it will not be affected by thermal expansion.

9. How long is the delivery time of the locating block?

We have a certain amount of stock for commonly used locating blocks, and some locating blocks need to be produced, which usually takes about a week. Large quantities of orders need to be separately determined for delivery.

10. What is the minimum order quantity for mold lock?

There is no minimum order requirement for our mold lock. Of course, if you plan to purchase too few quantities, it may not be very cost-effective for freight.

11. How to get the quotation of mold lock?

You can initiate an inquiry on this page, or send an email to tao@szthreeup.com for consultation. We will ship your mold lock by express delivery such as DHL or TNT. We can also arrange shipping for large quantities of orders.

      12. Why choose our mold lock?

Our company’s mold lock categories are diverse, which can meet your various purchasing needs. We use high-quality raw materials and better heat treatment to ensure the quality of your products. We are still doing OEM for some international companies. Under their strict procurement requirements, we are constantly improving our product level.