Abrasive Belt is a special abrasive product, which has no fixed size and needs to adjust the circumference of the abrasive belt according to the size of the user's equipment. The original sandpaper roll or sand cloth roll is mostly 1170mm in height * 100m in length.
So how does the abrasive belt splice together and withstand the stretching strength of the machine while continuously aligning?
The commonly used joint methods are: butt joint and overlap joint, or called docking joint and lining joint. The butt joint is divided into straight butt joint and sine wave butt joint according to the cutting edge shape.
It is commonly used in various abrasive belt joints, and removing abrasives at the joint is to avoid leaving marks on the joint during processing.
When using overlapped abrasive belts, pay attention to the direction of rotation. The upper layer of the joint should be the entering direction, so that the joint bears pressure and shear force when entering grinding. Shear force also helps to improve the force situation of the joint.
The overlapped abrasive belt is a case of a flat joint abrasive belt. A thin (about 0.075mm) but high-strength polyester film is used as the substrate downstream of the joint. This type of joint abrasive belt is suitable for high-speed grinding and precision grinding, and the direction is not restricted.
Sine wave joint is a newer form of joint. There are two shear forms of sine wave, both of which are beneficial to increasing the wave card strength of the material and reducing the bonding flanging phenomenon in the straight edge joint.
This not only allows thinner and less lining material to have greater tensile strength, but also makes the joint abrasive belt operate smoothly without leaving grinding marks.
Flat joint abrasive belt gradually replaces overlapping method because of the technological progress of joint adhesive and joint lining materials, the relative price decrease and the more unblocked channels to obtain these materials.
Cut the length and width according to the user's specifications, determine the appropriate joint angle, and cut the blank. The so-called joint angle refers to the angle between the joint edge and the rotation direction. The larger the joint angle, the shorter the joint edge and the smaller the corresponding joint strength. Vice versa.
Generally, the smaller the abrasive belt width, the smaller the selected joint angle, and the longer the joint edge, which can increase the joint area and improve the joint strength. The joint angle of the abrasive belt should be selected between 45°-85°.
Grinding the sand layer or paste layer off the joint position of the abrasive belt to ensure firm bonding and appropriate thickness. The bottom edge in the overlapping process is called the underhead edge, and the upper edge is called the over-head edge.
When grinding edges, the sand layer and bonding layer (sand layer) of the lower joint edge should be removed, and the paste layer on the upper joint edge should be ground off. In order to ensure that the joint thickness is consistent with the thickness of the grinding tool, some of the sand layer on the front of the upper joint edge may also need to be removed.
For lining joint, it is mainly to remove the paste on the back of the joint position, and generally do not remove the front sand layer or only slightly.
In the grinding process, the grinding of the abrasive layer is generally carried out using a diamond grinding wheel, and the removal of the bonding agent and partial base material is carried out using a abrasive belt. The back paste layer can be ground using a abrasive belt or wire brush.
The excellent grinding equipment now has four grinding heads for the bottom joint grinding process: two diamond grinding wheels, one positive abrasive belt, and one inclined abrasive belt. If an adhesive head is added, it is five.
There are generally three grinding heads for the upper joint grinding process: a abrasive belt, a wire brush, and a diamond grinding wheel (polishing the front sand layer). If an adhesive head is added, it is four.
The grinding of the bottom joint and the grinding of the upper joint can be performed on two separate devices or on one device at the same time.
Use a special adhesive coating machine to coat the joint adhesive on the polished joint surface. After it is half dry, press the two joints together and press them on a hot press joint machine. During the adhesive coating process, attention should be paid to the uniformity of the bonding agent and the appropriate thickness.
The pressure head of the joint machine itself will be heated, and the joint adhesive of the abrasive belt will be basically solidified during the pressing process. It can be cooled after being stored for a period of time.
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