The difference between brushing and polishing in stainless steel:

In terms of process, the brushing process is to make a regular and uniform surface texture on the surface of the workpiece. The general brushing lines are: thin stripes and circles. The polishing process is to make the surface of the workpiece completely flat, without any defects, and it looks smooth and translucent, showing a mirror surface.

In terms of movement, the wire brushing process does repeated movements on the equipment, while the polishing process is the movement trajectory done on the plane polishing machine. The two are different in principle, and the actual way is also different.

In production, wire brushing adopts professional wire brushing process equipment, and there are many kinds of polishing process equipment according to the shape of the polishing.

If a workpiece needs both wire brushing and polishing, which process is in the front and which one is behind?

From this situation, it should be considered from the effects of wire brushing and polishing on the surface treatment, as well as the principle of the process, we are not difficult to draw: polishing is in front, wire brushing is in the back. Only the surface of the workpiece should be polished and flat before brushing. Because the effect of brushing is only good, the brushing lines will be uniform, and the polishing is for brushing the foundation. In short, if the first brushing is polishing, not only the brushing effect is very poor, but the good brushing texture will be polished by the grinding disc during polishing, so there is no so-called brushing effect.

Precautions for stainless steel brushing

1. Brushing: Usually, the surface of the stainless steel surface is processed by mechanical friction to obtain straight lines, including wire brushing, and lines and ripples.

Processing quality standard: the thickness of the texture is uniform and uniform. The texture of each side of the product is natural and beautiful according to the design and construction requirements. The bending position of the product is allowed to have a slight messy texture that does not affect the appearance.

1 brushing process:

(1) The lines formed by different types of sandpaper are also different. Deeper. Therefore, the type of sandpaper must be indicated on the engineering brushing.

(2) brushing is directional: it must be indicated on the engineering brushing whether it is straight or horizontal brushing (indicated by double arrows).

(3) The brushing surface of the brushing workpiece must not have any raised parts, otherwise the raised parts will be flattened.

Note: Generally, after wire brushing, electroplating, oxidation and other treatments are required. For example: iron plating, aluminum oxidation. Due to the defects of the wire brushing machine, when designing wire brushing jigs for small workpieces and large holes in the workpiece To avoid poor quality of the workpiece after brushing.

2 Brushing machine functions and precautions:

Before brushing, the wire brushing machine must be adjusted to the appropriate height according to the thickness of the material.

The slower the conveyor belt speed, the finer the grinding, and the thicker the converse. If the feed depth is too large, the workpiece surface will be burned, so each feed should not be too much, it should be around 0.05mm.

The pressure of the pressure cylinder is too small, and the workpiece will not be pressed. The workpiece is thrown out by the centrifugal force of the roller. Too much pressure will increase the grinding resistance and affect the grinding effect. The effective brushing width of the wire brushing machine does not exceed 600mm. If the length direction is greater than 600mm and the width If the direction is less than 600mm, you must pay attention to the brushing direction, because the brushing direction is along the material feed direction.

Precautions for polishing stainless steel

Brightness grade of polished stainless steel

By visual inspection, the brightness of the surface of the polished parts is divided into 5 levels:

Level 1: White oxide film on the surface, no brightness;

Level 2: Slightly bright, with no clear outline;

Level 3: The brightness is good, and the outline can be seen;

Level 4: The surface is bright and the outline is clearly seen (equivalent to the surface quality of electrochemical polishing);

Level 5: Glossy like a mirror.

The general process of mechanical polishing is as follows:

(1) Rough throwing

After milling, EDM, grinding and other processes, the surface can be selected from 35 000-40 000 rpm rotating surface polishing machine or ultrasonic grinding machine for polishing. A common method is to remove the white electric spark layer by using wheels with a diameter of Φ 3mm and WA #400. Then there is manual whetstone grinding, with strip whetstone plus kerosene as a lubricant or coolant. The general order of use is #180 ~ #240 ~ #320 ~ #400 ~ #600 ~ #800 ~ #1000. Many mold makers choose to start with #400 in order to save time.

(2) Semi-precision polishing

Semi-precision polishing mainly uses sandpaper and kerosene. The number of sandpaper is: #400 ~ #600~ #800 ~ #1000 ~ #1200 ~ #1500. In fact, #1500 sandpaper only uses mold steel suitable for hardening (above 52HRC), but not for pre-hardened steel, because it may cause burns on the surface of pre-hardened steel parts.

(3) Fine polishing

Precision polishing mainly uses diamond abrasive paste. If the polishing cloth wheel is mixed with diamond grinding powder or grinding paste, the usual grinding sequence is 9 μ m (#1800 )~ 6 μ m (#3000 )~3 μ m (#8000 ). 9 μm diamond abrasive paste and polishing cloth wheel can be used to remove the hair-like wear marks left by #1200 and #1500 sandpaper. Then use sticky felt and diamond abrasive paste for polishing, the order is 1 μ m (#14000) ~ 1/2 μ m (#60000) ~ 1/4 μ m (#100000 ). The polishing process with an accuracy of more than 1 μm (including 1 μm) can be performed in a clean polishing room in the mold processing workshop. For more precise polishing, an absolutely clean space is necessary. Dust, smoke, dandruff and saliva foam can all be scrapped from the highly precise polished surface obtained after several hours of work.

Mechanical polishing: polishing with a belt polishing machine on the roller frame, first use 120# abrasive belt, throw it to the surface color when the time is up, change 240# abrasive belt, throw it to the surface color when the time is up, then change 800# abrasive belt, throw it to As soon as the surface color is reached, change the 1200# sand belt to throw the effect of decorative stainless steel plate.

Precautions for stainless steel polishing

Grinding with sandpaper or abrasive belt in the grinding operation is basically a polishing and cutting operation, leaving very fine lines on the surface of the steel plate. I have encountered troubles when using alumina as an abrasive, partly because of pressure problems. Any abrasive parts of the equipment, such as abrasive belts and grinding wheels, must not be used for other non-stainless steel materials before use. Because this will contaminate the stainless steel surface. In order to ensure the consistency of the surface processing, the new grinding wheel or belt should be tried on the scrap with the same composition in order to compare with the sample.