In China's metal processing industry, metal forming technology occupies a pivotal position. Among them, sheet metal processing, as an important branch of metal forming, is widely used in various fields. Metal stamping, as a common way of sheet metal processing, deforms the metal material through the stamping die to achieve product molding. In this process, stamping die plays a key role, especially progressive stamping die, which can realize continuous multi-process stamping, greatly improving production efficiency and product quality.
When the base plate is used on the machine tool, it is easier to set up and install fixtures by setting up threaded holes, reamed holes and slots, etc. It is generally made according to the shape of the machining center table, and its functions include adjusting the height of the workpiece, protecting the machine table, and adjusting the orientation of the workpiece to carry out simultaneous machining of multiple surfaces as needed.
1. Types of base plates and pedestals
Vertical machining centers mainly use the base plate. Horizontal machining centers use the base plate in addition to the base plate has a single-sided base, double-sided base and four-sided base.
Horizontal machining centers also use six-sided and eight-sided bases to accommodate various workpiece sizes.
2. Types of Base Plate and Base Fixture Mounting Surfaces
Base plate, base fixture mounting surface mounting T-slot form, bolt hole form, reference hole form. In addition, there are also self-machining types that are used in actual machining in order to make the machining center accuracy and fixture mounting surface accuracy as perfect as possible.
Since each machine tool has its own characteristics, such as the inclination of the floor of the factory where the machine is located, or the inclination of the spindle after years of use, it is possible to machine the remnants of the fixture mounting surface to fit the individual characteristics of the machine tool, and to make the fixture mounting surface more accurate. There is also a form of disassembly and assembly of workpieces and fixtures can be performed outside the machine tool: quick change of workpieces.
3.determine the size and positioning methods
Selection of the base plate, base, the first need to confirm the size and positioning method in advance. The basic size of horizontal machining centers are 400X400, 500X500, 630X630, 800X800, depending on the machine tool manufacturer, there are 300X300, 1000X1000 and other sizes, 550X550 and other special sizes are also produced by machine tool manufacturers. The size of vertical machining centers varies from machine tool manufacturer to machine tool manufacturer, and there is no special rule for the size. Each machine tool manufacturer has its own table dimensions, which can be found in the machine's instruction manual.
Horizontal machining centers are generally positioned by using table rests mounted in the X and Y directions, which are attached to the table rests to complete the positioning of the base plate and base. The position of the table resting block is generally set in the 0° and 270° orientation of the machine table, and the position of the table resting block varies according to the machine tool manufacturer. Vertical machining centers generally have a keyway in the center of the table. The keyway is used to position the base plate and base in the X direction, and then the T-slot is used to position the base plate and base in the Y direction.
However, not all T-slots can be accurately positioned, depending on the machine tool manufacturer, the machine has a positioning function of the T-slots generally only 1 or 2.
4. Confirm the maximum load of the machine tool
First confirm the maximum load of the machine tool, and then confirm the total weight of the workpiece, fixture, base plate, base, the total weight should never exceed the maximum load of the machine tool. Some designers also calculate the weight of the workpiece and base plate, base, forget to calculate the weight of the fixture, which should not be ignored.
If the total weight exceeds the maximum load capacity of the machine tool, you can choose to reduce the thickness of the base plate, reduce the thickness of the mounting surface of the base or the base into a hollow type and other methods, used to reduce the overall weight.
5. Confirmation of the height of the base and the maximum rotary diameter
Select the base plate, the maximum height of the machine tool when the base and the maximum rotary diameter must be confirmed in advance. Especially horizontal machining centers, the maximum rotary diameter is a matter that must be confirmed. Generally, the maximum rotary diameter is Φ630 for a base plate size of 400x400, and Φ800 for a base plate size of 500x500. The above two sizes are common, and there is no specific rule that requires the use of a base plate of these sizes. When the fixture is used to clamp the workpiece from top to bottom, the top of the fixture (the top of the bolt in the figure below) must be within the maximum rotary diameter.
6. Confirmation of machining range and stroke
Confirm in advance that the machinable range of the machine (spindle travel range) covers all the parts of the workpiece to be machined. Especially when using the milling cutter for machining the surface, when the cutter is withdrawn, whether the spindle travel can make the cutter completely out of the workpiece range must be considered in advance in the design, if you do not take into account the withdrawal of the cutter, to ensure that the surface accuracy is more difficult. When the milling cutter withdraws from the workpiece, a minimum distance of 10mm or more needs to be ensured with the workpiece, that is, the cutter needs to be allowed to completely leave the workpiece range.