Cutting of soft rubber (Ⅰ)
Cutting of soft rubber
Rubber is one of the material, with large difficulty in cutting and grinding. Shungji knife has much experience for the cutting tools.
(1) Classification of rubber and performance of soft rubber
There are many kinds of rubber, according to its source can be divided into natural rubber and synthetic rubber two categories, generally referred to as rubber, refers to soft rubber. It is according to the different performance of the use of different compounding agents, made of a variety of rubber products with different hardness. The other is a hard rubber that is vulcanized by adding 25% to 50% sulfur in raw rubber. The hardness and strength of hard rubber are relatively high, and it has excellent electrical insulation and stability against acids and bases
Like general non-metallic materials, soft rubber has an extremely low thermal conductivity [x=0.21W/(m·K)]. Its hardness is Shore A type 35~90, the tensile strength is 19.6~24.5MPa, the elongation is 500%~700%, the elastic die disk is very low (1.9~3.9MPa). Its important performance characteristics are in a wide temperature range (-50~150℃), with good elasticity, flexibility, variability and resilience.
(2) Cutting characteristics of soft rubber
According to the physical and mechanical properties of soft rubber, machinability grade classification, there are two performance indicators belong to the 9a level, is the most difficult to cut the material, so it has the following cutting characteristics.
Due to the small elastic modulus of soft rubber, elastic recovery is fast, it is easy to deform in cutting, and it is difficult to control dimensional accuracy and shape accuracy. Especially in the case of small surplus and the tool is not sharp, it is difficult to cut the chip.
Due to its hardness and strength is very low, the cutting tool is required to be particularly sharp and the wedge Angle of the tool is small, and the cutting edge is mainly cut, and the rounded edge is slightly increased, so it is difficult to cut. The tip part should grind out a polishing edge greater than the feed amount, otherwise the chips can not be separated from the workpiece even on the machined surface.
③ The thermal conductivity of soft rubber is very low, it is one of 350 of the general steel, plus the chip cutter wedge Angle is very small, the heat dissipation ability is poor, its elastic modulus is very small, the elastic recovery is fast, and the friction between the tool and the workpiece is intensified, it is easy to dull the tool wear, so it can not allow too high cutting speed.
④ When soft rubber is continuously cut, the chips are banded and continuously chip. This requires that the tool must have a large edge Angle, control the flow of chips, and avoid the chip winding on the workpiece or the tool, affecting the normal cutting.
⑤ Generally do not use cutting fluid when cutting, if you want to use, you can only use aqueous solution rather than cutting oil to prevent deterioration and deformation.
For further more, please contact Shungji knife.
