ZHEJIANG YITIAN PRECISION MACHINERY CO.,LTD
Wet pneumatic friction clutch crankshaft powerful press manufacturers and Ordinary punching machine completes precision stamping
Precision blanking is an advanced precision forming plastic processing technology. It uses a precision blanking die on a wet pneumatic friction clutch crankshaft powerful press or a modified general press to make the sheet material purely shear along the required contour under the state of three-dimensional compressive stress. Extrusion separation can obtain plate-shaped precision contour parts with smooth section, verticality, good flatness and high precision. The main technical quality indicators of the parts have reached or even surpassed cutting processing or other processing methods, and the surface quality can be comparable to reaming, precision drilling and precision turning.
The wet pneumatic friction clutch crankshaft powerful press technical level that can be achieved by the fine blanking process is: fine blanking shear surface roughness Ra=1.5-0.3mm; super fine blanking shear surface roughness Ra=0.2-0.1mm; dimensional accuracy: burr <0.03mm, collapse Angular depth: 10%-25% material thickness; shear plane perpendicularity: 89 degrees 30 minutes (maximum); surface unevenness: generally can be used without leveling; minimum aperture: (0.3-0. 7) material thickness .
From the formal point of view, wet pneumatic friction clutch crankshaft powerful press fine blanking is a separation process, but it is actually a plastic deformation process. To realize fine blanking, it must be ensured that no tearing occurs during the fine blanking process. In order to meet the requirements of fine blanking, several necessary process requirements:
If necessary, round the punch or die cutting edge to reduce the stress concentration at the cutting edge, avoid or delay the generation of cracks, and improve the stress state of the deformation zone.
The wet pneumatic friction clutch crankshaft powerful press blank holder force and back pressure are used to increase the hydrostatic pressure of the material in the deformation zone to improve the plasticity of the material.
The materials are pre-treated, or special materials are used.
Use suitable lubricants.
The shear surface roughness of precision blanking parts is evaluated according to GB131-83 with the average difference Ra value of contour arithmetic.
At present, the fine blanking process cannot completely eliminate the burrs, which are generated on the side of the punch. The size depends on the material of the part, the state of the cutting edge, the degree of wear of the part and the contour factor of the part. When the mold parts are sharp, the height of the burr is generally within 0.01-0,08mm.
Fine blanking process of ordinary press:
1. Refurbishment: high-precision guide pillar die set, single side C=(0.05-0.1)%t micro-clearance, sharp knife edge refurbishment mold, punching ordinary blanking, to obtain smooth and straight punching surface. The dimensional accuracy reaches IT6-IT9, and the surface finish Ra≥0.4mm.
2. Smooth punching: Use high-precision, micro or negative clearance, rounded edge or stepped multi-layer edge punching die to obtain a smooth and straight punching surface. Dimensional accuracy IT8-IT10, surface finish Ra≥0.4mm.
3. Simple fine blanking: use hydraulic die set or three-action special structure die to implement fine blanking methods such as powerful pressing plate and opposite die to fine blank small workpieces. The structure is complex, the manufacturing technology requirements are high, and hydraulic devices are required. Dimensional accuracy IT7-IT10, surface finish Ra≥0.8mm.
Fine blanking process of wet pneumatic friction clutch crankshaft powerful press:
1. Powerful pressing plate fine blanking: often use the V-shaped gear ring strong pressing plate and the lower counter top pressing plate to clamp the sheet, and perform precision blanking with a small fine blanking gap of ≤0.5%t. The blanking die is a straight-walled cutting edge with a small rounded corner of R0.1mm. Dimensional accuracy IT6-IT9, surface finish Ra≥0.2mm, with corners and burrs.