1、 Clamping of workpiece on flat tongs
1. Clamping of blank parts: select a large and flat blank surface on the blank part as the rough datum surface, and lean it against the fixed jaw surface. A copper sheet shall be placed between the jaw and the workpiece blank surface to prevent damage to the jaw. Gently clamp the workpiece, and use the scratch disc to correct the upper plane position of the blank. Clamp the workpiece after it meets the requirements.
2. Clamping of rough machined workpiece: select a large rough machined surface on the workpiece as the reference plane, and clamp it against the fixed jaw surface of the flat jaw pliers or the guide rail surface of the pliers body.
When the reference plane of the workpiece is close to the fixed jaw surface, a round bar can be placed between the movable jaw and the workpiece. The round bar should be parallel to the upper plane of the jaw, and its position is higher in the middle of the height of the part of the jaw holding the workpiece. By clamping the workpiece with a round bar, it can ensure that the reference plane of the workpiece fits well with the fixed jaw surface.
When the reference surface of the workpiece is close to the guide rail surface of the clamp body, a parallel sizing block should be placed between the workpiece and the guide rail. In order to make the reference surface of the workpiece parallel to the guide rail surface, slightly tighten it, gently tap the workpiece with an aluminum or copper hammer, and try to move the sizing block by hand. When it is not loose, the workpiece fits well with the sizing block, and then clamp it.
2、 Clamp workpiece with pressing plate
When the reference surface of the workpiece is close to the guide rail surface of the clamp body, a parallel sizing block should be placed between the workpiece and the guide rail. In order to make the reference surface of the workpiece parallel to the guide rail surface, slightly tighten it, gently tap the workpiece with an aluminum or copper hammer, and try to move the sizing block by hand. When it is not loose, the workpiece fits well with the sizing block, and then clamp it.
1. Method of clamping workpiece with pressing plate
The tools used to clamp workpiece with pressing plate on milling machine are relatively simple, mainly including pressing plate, sizing block, T-bolt (or T-nut) and nut. The pressing plate has many shapes, which can meet the needs of clamping workpieces of different shapes.
When using the pressing plate to clamp the workpiece, more than two pressing plates should be selected. One end of the pressing plate is on the workpiece and the other end is on the sizing block. The height of the sizing block should be equal to or slightly higher than the height of the compressed part of the workpiece. The distance between the middle bolt and the workpiece should be slightly less than the distance between the bolt and the sizing block. When using the pressing plate, a washer should be placed between the nut and the plane of the pressing plate.
2. Precautions when clamping workpiece with pressing plate
(1) On the worktable of the milling machine, it is not allowed to drag the rough surface of castings and forgings. When clamping, a copper sheet should be placed between the workpiece and the worktable to avoid damaging the worktable.
(2) When clamping the machined surface of the workpiece with a pressing plate, a copper sheet shall be placed between the pressing plate and the workpiece surface to avoid crushing the machined surface of the workpiece.
(3) The position of the pressing plate should be placed correctly, and it should be pressed on the part with the best rigidity of the workpiece to prevent deformation of the workpiece. If the clamping part of the workpiece is suspended, the workpiece should be padded.
(4) The bolts shall be tightened to ensure that the workpiece will not move due to insufficient pressure during milling and damage the workpiece, cutter and machine tool.