Automatic detection! Manipulators rely on it to automate loading and unloading

In machining, the dimensions made will be completely correct only if the positioning surface and the positioning datum are in close proximity. Depending on the degree of adhesion between the positioning surface and the reference surface, the gas pressure range of the detection air hole on the fixture will be different. If it does not fit, the pressure difference exceeds the range and an alarm signal will be output, and the equipment will stop running to avoid waste. Regarding the airtight inspection fixture, let's first look directly at the design cases of two rear-pull mandrel air inspection fixtures.

1. Standard scheme of outer diameter fixture

Figure 1 Outer diameter fixture structure

Fixture action description: After the workpiece is placed in the ear-shaped corresponding indicator point, the bottom backer (marked in purple) is used as the reference, and the clamping edge of the jacket and the workpiece move back together, so that the positioning surface better fits the reference surface.

Figure 2 Reference plane of the external expansion fixture

Second, the internal expansion fixture program

Figure 3 Internal expansion fixture

Fixture action description: After the workpiece is put in, take the bottom backing (marked in blue) as the reference, the edge of the expansion sleeve is tightened, and the side moves back together with the workpiece, so that the positioning surface better fits the reference surface.

Three, case application

The characteristics of the above two rear-pull mandrel gas inspection fixtures are as follows:

1. The expansion of the sleeve side and the back movement of the workpiece can correct some deviations of the workpiece placement.

2. There is a detection air hole on the backer, and when there is chip accumulation or other conditions that cause it to not be close to the reference surface, it will alarm and stop to prevent the production of products with out-of-accuracy.

3. Within a certain size range, to replace the same type of product, only need to replace the backing and expansion sleeve, reducing the time and economic cost due to product replacement.

4. The expansion sleeve structure is a completely separated metal-to-metal infusion rubber, which has a larger contact area between the parallel expansion and the workpiece, and has a shock absorption effect.

Figure 5 Pouring rubber expansion sleeve

5. The unilateral clamping and loosening range of the expansion sleeve reaches 0.3mm (automatic selection), which is suitable for automatic production by manipulators.

6. Double anti-aircraft pull design, better extend the life of the expansion sleeve.

Figure 6 Example of gas inspection construction

Four, principle display

In the above design case, after using the air tightness detection, the accuracy of the workpiece positioning can be detected in real time at any time, and the scrapped workpiece caused by the entry of debris and foreign objects can be eliminated. It is suitable for high-volume and stable production, especially the use of machining automation at present.

Figure 7 Back-pull vulcanized rubber internal expansion fixture

The high-precision air-tight inspection vulcanized glue-filling clamping system is divided into two categories: back-pull internal expansion clamps and back-pull outer-circular clamps. They are suitable for hydraulic and pneumatic tooling of CNC lathes and machining centers. They have the following characteristics:

1. Parallel clamping, the contact area of the expansion sleeve is larger, the line contact between the ordinary collet and the workpiece is changed to surface contact, and the workpiece is not easy to deform. When the size of the bar material changes, the chuck flap can maintain the parallelism with the bar material. Parallel clamping minimizes the "back" phenomenon of the bar, and only a smaller pull rod pull force is required to achieve the same clamping capacity as a traditional chuck. Back-pull design, that is, the expansion sleeve moves back, driving the workpiece to lean back, and the end surface is more closely positioned.

Figure 8 Rear pull type vulcanized rubber outer diameter clamp

2. The elastic grooves are connected by vulcanized silicon rubber (as shown in Figure 9), which can be matched with the workpiece to achieve a large gap, and has a clamping range of ±0.5mm than the nominal size. Within this range, it can adapt to the size of the bar. The collet needs to be replaced. Adapt to the manipulator, not afraid of empty pulling and scrapping.

Figure 9 Sectional view of vulcanized potting

3. Possess a certain degree of shock absorption ability to reduce the loss of roughness caused by machine tool or tool vibration.

4. Vulcanized silicone rubber will not become brittle and can block the coolant. Due to this sealed design, it can prevent chips from entering the collet system and at the same time ensure the long life of the collet.

5. The chuck flap has good opening and closing synchronization, high clamping accuracy, and the clamping accuracy can be controlled within 0.010mm, which is much higher than the clamping accuracy of the hydraulic chuck 0.03mm.

6. Equipped with air tightness detection function. If the axis of the workpiece is deviated from the axis of the spindle when the workpiece is installed, the gas will overflow to trigger the pressure detector, send a signal to the machine tool control system, and generate a prompt signal to force the machine to stop, which plays a role of automatic error prevention .

Conclusion

Parts produced with the above fixtures have greatly reduced roundness and parallelism defects, and can also avoid poor quality caused by improper clamping and failure of the chuck flap. It is especially suitable for automated production lines.