Axial clamping device in milling of the hottest ha

2022-09-23
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Axial clamping device in hard material milling

the die workshop uses the combined device of tool clamping to maximize the performance of small-diameter tools

Users of machining centers are faced with many choices of tool clamping. All kinds of clamping mechanisms, including fixing screws, clamps, hot sleeve systems and water pressure, can do the same thing in general, and they can clamp the handle while maintaining concentricity and hardness

however, the extent to which various mechanical devices achieve these two goals in different application fields is still different. In addition, special clamping companies have further expanded the scope of their application of clamping devices. In order to complete a specific work in a specific workshop, the correct selection of clamping device becomes more and more difficult

the processing workshop at impact forge in Indiana, Columbus is facing the challenge of requiring multiple cards at one time. The small tools processed in this workshop have a long mounting length. These jobs include not only limited tool access, but also the processing of hard materials

forging die processing process in impact forge processing workshop

the tool clamping scheme developed by this workshop is composed of multiple clamping devices working together

there is a ruler that can not only explain how deep the cavity is, but also explain how small the clearance angle of the hollow wall is

specific work

the forging die processing process in the workshop is mainly to reprocess some existing dies that have been repaired in welding. Doug Lynch, a process programmer, explained that the hardness of welding dies with a hardness of 50rc is higher than before

rough machining and finish machining can be carried out in either of the two Okuma horizontal machining centers. Rough machining includes clamping an end milling cutter with a diameter of 1in (1in=0.0254m) on the clamping table of the set screw. In contrast, it is more difficult to install the card for finishing, because the small diameter of the die requires the diameter of the end mill to be less than 0.030in. At the same time, when processing the grooves and small clearance angles inside the workpiece, a clamping scheme is needed. New polyethylene and recycled polyethylene make these small tools fully close to the surface for processing

in the past, workshops used hot sleeve clamping devices to achieve these purposes. Without moving the workpiece, the hot sleeve fixture uses the principle of thermal expansion and cold contraction. When heated, the fixture will expand and become larger, and the tool will be clamped, and then when cooled, the fixture will shrink again. The hot sleeve provides a way to clamp small tools. The clamps in this way usually have a very simple shape and can clamp the tools concentrically. These media are non-toxic and harmless

Mr. Lynch said that the problem is that the clamping force of the heat sleeve is proportional to the expansion and contraction, which are related to the size of the hole. A small enough hole can be suitable for the clamping of small and medium-sized tools in the workshop, and the clamping force generated by it is relatively small. During processing, it is found that using the small-diameter end milling cutter of Melin (Cleveland, Ohio) Company may achieve more efficient cutting. There is an exception, if the cutting force is too high, the hot sleeve fixture will release the small-sized tool. In other words, machining centers and tools can complete machining, but fixtures are the limiting factor

One of the schemes developed by the workshop is the "tribos" system from Schunk (Morrisville, North Carolina). This system uses the rebound force of metal to clamp the tool, which is very similar to hot sleeve clamping. The difference is that it uses mechanical force to open the hole

The other part of the impact forge workshop plan is to maintain an extension of tribos within the hydraulic card loading

here is the clamping device. Pull up the rod to make the fixture drill a round hole, which makes the tool can be embedded

longer life

the following picture shows the card loading device of the tribos system. The shape of the fixture hole is very common, but it is usually imagined as an ideal circle. When the fixture is held in this way, the tool can be inserted. The released force will make the fixture recoil and clamp the tool concentrically at the same time

the processing workshop integrates the fixture technology and Jinfa technology to provide three types of spray free materials: ① the metal paint effect is combined, and tribos is clamped by the hydraulic device

this system is used to clamp the tool. The processing workshop of impact forge can make the ball head tool of Melin company with a diameter of 0.03in and a stiffness of 50rc run, and the running state is 8500r/min, 20ipm, and the cutting depth is 0.003in. Mr. Lynch said that when small tools are clamped through hot sleeves, the workshop cannot guarantee these parameters

when it comes to holding the extension to clamp the tool, the processing workshop finds that any clamping device that generates force by the elasticity of metal - including hot sleeve system and chuck - is much inferior to the hydraulic fixture that can also complete the task. It is better to clamp the extension of the tribos system with a hydraulic clamp than with a chuck system. The former can increase the service life of the tool by 3-4 times

water pressure fixture uses water pressure to transmit force. This fixture contains a hydraulic fluid reservoir. The user applies pressure to the liquid by tightening the screw, and then the pressure is distributed around the metal sleeve to clamp the handle. The compression of this flexible bushing can clamp the tool. In addition, the hydraulic press fluid provides vibration damping as a secondary gain. Mr. Lynch attributed this damping to the improvement of tool life, which will affect the service life of the device

the processing workshop uses the "tendo" hydraulic fixture also from Schunk. Through consideration of other hydraulic fixtures, Mr. Lynch said that the service life of fixtures should be paid more attention than that of tools. When the fixture is idle, accidentally tightening the screw will compress the bushing, resulting in damage to the fixture. Tendo's design just avoids this problem, because through a separate mechanical device, the screw is only tightened to a pre stop state to trigger the water pressure. In this way, the torque wrench is unnecessary, and the screw can be tightened when the fixture is idle

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