Search This Blog

Working principle of slow wire processing

 Slow wire walking, also called low-speed wire walking, is a kind of CNC machining machine tool that uses continuously moving fine metal wire as an electrode to pulse spark discharge on the workpiece to generate a high temperature of over 6000 degrees, ablate metal and cut into a workpiece. The principle of wire processing is the phenomenon that there is a gap between the wire electrode and the workpiece, and the metal is removed by continuous discharge. Since the slow-moving wire cutting machine adopts the method of wire electrode continuous feeding, that is, the wire electrode is processed during the movement, so even if the wire electrode is worn out, it can be continuously supplemented, so it can improve the machining accuracy of the parts and slow the wire. The surface roughness of the workpiece processed by the cutting machine can usually reach Ra=0.8μm and above, and the roundness error, linear error and dimensional error of the slow-moving wire cutting machine are much better t

Classification of CNC Machining Occupation Levels

1. Blue-collar layer:   That is, CNC machining operation technicians, proficient in machining and CNC machining process knowledge, proficient in the operation and manual programming of CNC machine tools (attributes: automated machine tools), understand automatic programming and simple maintenance of CNC machine tools (attributes: automated machine tools), such There is a large market demand for personnel, and they are suitable for operating workers of CNC machine tools (attributes: automated machine tools) in the workshop, but due to their single knowledge, their wages will not be much higher.   2. Gray collar layer:   One, CNC machining programmer:   Master the knowledge of 5 Axis CNC machining Aluminum   technology and the operation of CNC machine tools (attributes: automated machine tools), be familiar with the design and manufacturing expertise of complex molds (title: mother of industry), and be proficient in 3D CAD/CAM software, such as UG, GOOGLE PRO/E, etc. ; Familiar with CNC

Hydrostatic guideway of CNC machining lathe

The static pressure slide rail (TTW guide) of the CNC machining lathe transfers the oil with a certain pressure through the throttle to the oil cavity between the sliding surfaces of the slide rail (TTW guide) to form a pressure oil film to float the moving parts , Make the sliding rail (TTW guide) surface in a pure liquid friction state.   CNC machining General CNC machining usually refers to computer digital control precision machining, CNC machining lathe, CNC machining milling machine, CNC machining c17200   beryllium   copper   and milling machine, etc. The feed route of finishing is basically carried out along the part contour sequence. Therefore, the focus of determining the feed route is to determine the feed route of rough machining and idle stroke. In the numerical control processing, the control system issues instructions to make the tool perform various motions that meet the requirements, and the shape and size of the workpiece are expressed in the form of numbers and lette

Example of processing pressed parts –Metal clip

Explanation of parts analysis

1. Part shape and general requirements

As shown in Figure 1-1, the material must be stainless steel, the material thickness must be 0.5 mm, and the dimensional accuracy of the workpiece must meet the drawing requirements. Unmarked accuracy according to IT12 level, the production program has an annual production of 100,000 pieces.

Part process analysis

The shape of the workpiece is simple, the size and thickness are modest, and it is generally mass-produced. Although it belongs to normal press parts, please note the following points when designing cold press dies.

2. The outline and structure of the part is simple, but some hole machining needs to be considered.

  • A, two two-hole position requirements,
  • B, by assembly
  • C, the two holes must have the same
  • D, shaft requirements
  • E, its value is 0.15 mm.

The difficulty in processing this portion is mainly the positioning of the center distance of the hole 2.

Since some holes have a small diameter and a particular batch size, the design of the mold material and structure should be emphasized to guarantee a particular mold life.

Process planning decisions

According to the analysis of the process of the workpiece, the basic process includes punching, punching and bending. There are several types of processing methods and their rational processing methods in the following order.

  • 1, blanking-punch-bending, single process stamping.
  • 2, blanking-bending-punch, single process stamping.
  • 3, blanking punching-bending ribs, compound stamping.

Scheme 1) It is a single step stamping die.

It is not suitable to adopt this method because this part has some production batch, too many steps, reduces the accuracy of the product, and the production efficiency of this method is not suitable for mass production.

Scheme 2) It is also a one-step stamping die.

In addition to the drawbacks of Method 1, it is difficult to secure the position accuracy of the holes, and it is difficult to secure the lack of positioning accuracy in bending, so it is not appropriate to adopt this method.

Scheme 3) Composite stamping die.

Due to the structure of the parts, the thickness of the material is thin, and punching and punching are completed once. Therefore, it is best to adopt this scheme.
The specific plan is as follows.

Process parameter determination

1. Calculation of blank size

Calculation of external dimension length

The relative bend radii of the part are:

R / t = 2 / 0.5 = 4> 0.5

Where X is the experimentally determined strain-neutral layer displacement coefficient.

T material thickness

Apparently, for parts belonging to large bend radius members, the radius of curvature ρ of the neutral bend deformation zone should be determined.

Textbook p145 Neutral position calculation formula

Where X is the experimentally determined strain-neutral layer displacement coefficient.

Table 4-5 from p145 of the textbook takes X 0.42

Such:

  • ρ = R + Xt
  • = 2 + 0.42 × 0.5
  • = 2.21mm
  • Calculation formula for blank length of curved surface parts with large fillet radius (R> 0.5t)
  • L = ∑L straight + ∑L bend
  • L bend = [(180-a) / 180] * πρ

Therefore, the length of the part is shown in Figure 2-2.

  • L = LAB + LBC + LCD + LDE + LEF + LFG + LGH + LHI + LIJ + LJK + LKL
  • L = 3 + 3.0342 + 8.54 + 14 + 1 + 1 + 1.8028 + 13 + 1.8028 + 1 + 2
  • L = 50.1798

The DE segment belongs to the process settings. The purpose is to reduce bending springback. The length of the DE segment is calculated as a straight line because it has a large radius and can be considered a straight line.

1. The width of the contour is calculated.

Considering the use of sheet materials and the convenience of layout, the process size of the work created by CAD is as follows. Outline width is L = 53.74 mm

2.Layout size calculation

Determining edge value

From Table 3-14 on page 46 of the textbook, we can see that the value of a1 between workpieces L> 50 is 2.2 * 0.8 = 1.76.

The value of side a is 2.5 * 0.8 = 2.

3. Calculate the width of the material

For convenience of mold design, the strip width calculation formula using the non-side pressure device feed method is as follows.

  • B = (D + 2a + Z) 0 −δ
  • formula
  • B-Basic size of strip width.
  • D-Maximum size of part profile in strip width direction
  • a –Side edge
  • Z—Gap between the guide plate and the widest strip
  • Δ—Negative deviation of strip width
  • Margin a is as above
  • Gap δ, shear tolerance Z Check textbook p47 Table 3-17 Measured value δ = 0.5mm, Z = 0.5mm
  • It is calculated by the above formula. B = (53.74 + 2 * 2 + 0.5> 0 –0.5 = 56.240 –0.5 mm)

Calculation step distance

Development view of parts (see Figure 2-3 on the right)
Generated effective horizontal dimension Ls = 53.74mm

The formula for calculating the step interval is as follows:

  • L = Ls + a1
  • Where L is the step interval
  • Ls-horizontal effective size
  • A1-margin
  • L = 53.74 + 2 = 55.74mm

The nesting from which you can get the mold is:

According to the requirements, the material board specifications are 1500 x 800 x 0.5. Each board can cut 14 1500 x 56 strips with a material utilization of over 80%.

Calculate material utilization rate

  • Textbook p43 Style 3-19
  • η = nA / BL × 100%
  • η –About material use
  • A-The actual area of ​​the blanking area within one step.
  • B-Strip width
  • L-Strip length
  • n –Total number of blanks on the sheet
  • η = 28 × 1932.765 / (56 × 1500) = 65%

Link to this article:Example of processing pressed parts --Metal clip

Reprint Statement: If there are no special instructions, all articles on this site are original. Please indicate the source for reprinting.:Cnc Machining,Thank

Contact Us


Get In Touch or Get A Quote

Need an expert? you are more than welcomed to
leave your contact info and we will be in touch shortly
YOUR COMPANY
Sifangyuan Industrial Park, Xinshapu, Huaide Community
Humen town, Dongguan City, Guangdong Province. 
860769-82886112
860769-82886112