First place: chuck
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Century-old clamps are still busy in machine shops. Its classicness is self-evident. There are more chucks than lathes in the workshop. A lathe would not function without a chuck.
Second place: T-shaped workbench
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Don't look at it because it is inconspicuous at ordinary times. If you find that your machine tool does not have a T-shaped worktable another day, you will definitely be at a loss.
Third place: Combination of T-block, screw, pressure plate and nut
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No matter how awesome your other fixtures are, without the combination of T-block, screw, pressure plate and nut, it will be difficult to install them on the machine tool (for milling machines and machining centers). If you don't believe it, just give it a try.
Fourth place: EROWA fixture
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It can guarantee a repeat positioning accuracy of /-0.002mm. The electrode cannot work without it; four-axis machining cannot work without it; five-axis machining cannot work without it.
Fifth place: Vise; and his brother Max
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If the workpiece cannot be pressed by the pressure plate, you should consider clamping it with a vise/maximum clamp.
Sixth place: Spindle and tool holder
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The spindle and tool handle are the crystallization of top human wisdom and cutting-edge technology.
Seventh place: Magnetic platform
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How to more easily place parts without clamping positions on the workbench for you to process? See how he did it?
Eighth place: Spring collet/collet
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How to use fewer tool holders to solve the clamping problem of tools with various specifications? Here you can find the answer.
Ninth place: Pneumatic cylinder clamp
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The essence of automatic clamping. Among the many clamps, workers probably like pneumatic clamps the most.
Tenth place: Dividing head
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What was once such a beautiful place is now in decline. It's all the fault of the indexing spindle. So please rank tenth.
Key points in designing various fixtures
1. Drilling machine fixture
The obvious feature of the drill press fixture is that it is equipped with a drill bushing to guide the drill bit. The drill bushing is installed on the drill template. It is customary to call the drill press fixture a "drill template".
(1) Main types of drilling dies and their structural characteristics
According to the distribution of the holes to be processed on the workpiece and the production type of the workpiece, the structure of the drilling die has various forms such as fixed type, rotary type, flipping type, swing type and sliding column type.
1. Fixed drilling die
2. Rotary drilling die
3． Flip-type drilling die
4. Sliding column drilling die
5. Cover type drilling die (removable drill template type drilling die)
(2) Key points in the design of drilling machine fixtures
1. Drill bushing
The function of the drill bushing is to determine the axis position of drill bits, reamers and other tools to prevent the tools from deflecting during processing. According to the usage characteristics, drill bushings can be divided into fixed, replaceable, quick-change and other structural forms.
(1) Fixed drill bushing
(2) Replaceable drill sleeve
(3) Quick change drill bushing
(4) Special drill bushing
2. drill template
Common drilling templates have four structural forms: fixed, hinged, detachable, and hanging.
(1) Fixed drilling template
(2) Hinge drill template
(3) Hanging drilling template
3． Determination of drill bushing position dimensions and tolerances
The position of the drill sleeve on the fixture is marked based on the positioning surface of the positioning element or the axis of the positioning element. The position size of the drill sleeve is based on the average size of the corresponding size of the workpiece. The tolerance is 1/2~1/5 of the corresponding size tolerance of the workpiece. The deviation is symmetrically marked.
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2. Milling machine fixture
Milling is an intermittent cutting and is prone to vibration. The force-bearing parts of the milling machine fixture must have sufficient strength and rigidity. The clamping force provided by the clamping mechanism should be large enough and must have good self-locking performance. Tool setting blocks and positioning keys are unique elements of milling machine fixtures. The tool setting block is used to determine the positional relationship of the milling cutter relative to the fixture positioning component; the positioning key is used to determine the positional relationship of the fixture relative to the machine tool.
1. Tool setting device
The position of the tool block working surface on the fixture is marked based on the positioning surface of the positioning element or the axis of the positioning element. Its position size can be calculated based on the process size and feeler gauge size. Its tolerance is generally taken as 1/5 to 1/2 of the corresponding process size tolerance, and the deviation is symmetrically marked.
2. Positioning key
The correct position of the milling machine clamp and the machine tool is determined by the cooperation of two positioning keys installed in the longitudinal slot on the bottom surface of the clamp body and the T-shaped slot on the machine tool workbench. Commonly used positioning keys are rectangular cross-section structures. In order to reduce positioning errors, the installation distance between the two positioning keys should be as large as possible.
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3. Lathe fixture
Lathe fixtures are generally used to process rotary parts. During turning, the lathe spindle drives the workpiece to rotate through the fixture. When designing this type of fixture, attention should be paid to solving the mass balance issues and operational safety issues caused by the rotation of the fixture.
4. Combined fixture
A combination fixture is a fixture assembled from a set of pre-manufactured standard components and components. After completing the specified processing tasks with the combined fixture, it can be easily disassembled. Used components and assemblies are cleaned and stored until the next time the fixture is assembled. The combination fixture is the most standardized, serialized and universal fixture among machine tool fixtures. Its basic characteristics are: flexible structure, components that can be reused for a long time, and short design and assembly cycle. The disadvantages of the combined fixture are: larger size, poor rigidity, and large one-time investment in purchasing components and components. The combined fixture is suitable for processing workpieces with high positional accuracy requirements in single-piece and small-batch production, and is often used in trial production of new products and completion of temporary assault tasks.
5. Accompanying fixtures
The accompanying fixture is a mobile fixture used in automatic production lines. In addition to positioning and clamping the workpiece, the accompanying fixture also carries the processed workpiece and transports it to the machine tool fixture of each machine tool according to the process flow of the automatic production line. The machine tool fixture positions and clamps it.
