37. What two aspects does positioning error include? What are the methods for calculating positioning error?

There are two aspects of positioning error. 1. The positioning error caused by inaccurate production of the positioning surface of the workpiece or the positioning components on the fixture is called reference position error. 2. The positioning error caused by the misalignment of the process datum and positioning datum of the workpiece is called datum misalignment. error

38. Basic requirements for the design of workpiece clamping devices.

1. The correct position obtained when positioning the workpiece should be maintained during the clamping process.

2. The clamping force should be appropriate. The clamping mechanism should be able to ensure that the workpiece does not loosen or vibrate during the processing. At the same time, it should avoid inappropriate deformation and surface damage of the workpiece. The clamping mechanism should generally have a self-locking function.

3. The clamping device should be easy to operate, labor-saving and safe. 4. The complexity and automation of the clamping device should be compatible with the production batch and production method. The structural design should be simple and compact and use standardized components as much as possible.

39. What are the three elements to determine the clamping force? What are the principles for selecting the direction of clamping force and the point of action?

Size, direction, point of action.

The selection of clamping force direction should generally follow the following principles:

1. The direction of the clamping force should be conducive to the accurate positioning of the workpiece without damaging the positioning. For this reason, it is generally required that the main clamping force points vertically to the positioning surface.

2. The direction of clamping force should be consistent with the direction of greater stiffness of the workpiece to reduce the clamping deformation of the workpiece.

3. The direction of clamping force should be as consistent as possible with the direction of cutting force and workpiece gravity to reduce the required clamping force.

General principles for selecting the clamping force application point:

1. The clamping force application point should be facing the support surface formed by the support element to ensure that the positioning of the workpiece remains unchanged.

2. The clamping force application point should be in a relatively rigid position to reduce the clamping deformation of the workpiece.

3. The clamping force application point should be as close as possible to the processing surface to reduce the turning moment caused by the cutting force on the workpiece.

40. What are the commonly used clamping mechanisms? Focus on analyzing and mastering the wedge clamping mechanism.

1. Inclined wedge clamping structure 2. Spiral clamping structure 3. Eccentric clamping structure 4. Hinge clamping structure 5. Centering clamping structure 6. Linkage clamping structure

41. How to classify drilling molds according to their structural characteristics? How to classify drill sleeves according to their structural characteristics? What are the categories of specific connection methods between drill templates and clamps?

The drilling mold is based on the total structural characteristics:

1. Fixed drilling die 2. Rotary drilling die 3. Flip-type drilling die 4. Cover type drilling die 5. Sliding column drilling die

Drilling mold structural characteristics classification:

1. Fixed drilling mold 2. Replaceable drilling mold 3. Quick-change drilling mold 4. Special drilling mold

The specific connection method of drilling template and clamp:

Fixed Hinged Separate Suspension