Abrasives Belt Joints

For an endless abrasive belt, the joint is the weakest part. If the belt joint is not made well, it will become the most vulnerable part of the belt and affect the use of the belt. If the joint part is too thick, it will affect the flexibility of the abrasive belt, and also increase the friction force of the sanding belt on the workpiece, leaving grinding marks on the workpiece. However, if the joint part used binder is sensitive to temperature and medium, the abrasive belt also could be broken. Therefore, sanding belt joints should have the following 3 properties:

1. High tear resistance, high tensile strength and shear strength

2. High resistance to heat and medium erosion

3. The thickness of the joint should be not much different from that of other parts. And fine-grained abrasive belts should have higher requirements.

Belt joint types generally fall into two different categories:

a) the lap joint which is formed by alternately tapered ends that are laid and fused on top of each other and

b) the butt joint which is formed by two ends that abut each other and are joined by means of a narrow strip of (mostly fibre-reinforced) tape either on the front or the reverse side of the belt.

Since there are additional variations within these two types of joint categories, the belt can be perfectly adjusted to the grinding task at hand.

We use the following types of belt joints for abrasive belts:

No. 1:  Belt ends are overlapped with no grain removed off top of splice. Offers maximum protection against wear for soft contact wheels, or slack of belt operations. Also recommended on paper belts.

No. 2:  Belt ends are overlapped with partial grain removed off top of splice (partial top-skived). Smooth running over hard contact wheels for cloth belts 80 grits or finer. Good for edge sanding on bull nose.

No. 3:  Similar to Type 4 joint except the two belt ends are cut in an interlocking configuration, or zig-zag. Grit size 50 or finer only. Ideal joint in glass grinding applications.

No. 4:  Butt splice, in which belt ends are butted together and joined by high strength tape on underside of joint. Allows belt to run in either direction for greater belt life and convenience. Smooth running. Most popular splice, suitable for a wide

variety of applications and belt sizes.

No. 5:  Belt ends are overlapped with complete grain removal off top of splice (fully top-skived). For woodworking applications where minimum. Joint thickness and flexibility is Important.

No. 6: “T”Joints, a top skived 4 butt Joint used on cloth belts 150 and finer for platen sanding operations on wide belt sanders. Not used on paper belts.

According to the size, thickness and grit of sand belt, we also provide different sand belt joints for you to choose. Yihong provides you with different abrasives