How do I cut the PCB circuit board?
The shearing machine is capable of handling various sizes and providing precise repeated dimensions. Large machines can cut hundreds of kilograms of substrates each hour.
Sawing is another method of cutting a substrate. Although the size tolerance of this method is similar to that of shearing (0.3 - 0.5 rnrn), this method is preferable because its cutting edges are very smooth and tidy.In the manufacture of printed circuit boards, most of the circular saws are removable. The speed range of saw blade is adjustable from 2000 to 6000r/rnin. But once the cutting speed is set, it can not change any more. It is achieved by heavy pulleys with more than one V belt.High speed steel blade diameter is about 3000rnrn, it can be at a rate of 2000 - 3000r/rnin paper cutting material on the circumference of each 1cm was approximately 1. 2- 1.5 teeth. For epoxy glass substrates, blades using tungsten carbide blades. The diamond wheel cuts better, although it has a large investment at the start, but it is very useful for future work because of its long service life and improved edge cutting effect.
The angle between the two blades is to be selected according to the thickness of the cutting material. The thicker the material, the greater the angle required. If the gap between the shear angle is too large or two blades are too wide, a plate cracking in a paper cutting substrate, while for epoxy glass substrate, the material has a certain flexural strength, even if there is no crack, board will deformation. In order to keep the edge of the panel clean during shearing, the material can be heated to a temperature range of 30-100 degrees.In order to obtain a neat cut, the board must be firmly pressed down by a spring device to prevent any unavoidable movement of the board during the shearing process. In addition, the disparity can also lead to a tolerance of 0.3 0.5rnrn, which should be reduced to a minimum, can improve the accuracy of using angle.
The shearing of the laminate can be either manual or electrical mechanical operation, regardless of which method has the same characteristics in operation. The shears usually have a set of adjustable shear blades, as shown in figure 10-1. The blade is rectangular, the bottom edge is about 7 DEG angle adjustable, cutting length can reach 1000mm, the vertical angle between two blades are usually the best selection between 1 - 1.5 degrees, the use of epoxy glass substrate can reach the maximum of 4 degrees, two blade cutting edge gap between less than 0.25mm.
Shearing is the first step in the mechanical operation of a printed circuit board. The shape and outline can be given by shearing. The basic cutting method is applicable to a wide variety of substrates, usually of no more than 2mm. When the cutting board is more than 2mm, the edge of the cutting will appear rough and irregular, so this method is not generally used.
