Rolling quality problems and improvement measures
1 Introduction
In recent years, bearing sales market users often encounter some common quality problems. These problems, most of the industry has been resolved, but a small number of plants did not attract enough attention, resulting in substandard product quality. These will now be summarized common quality problems, suggest improvements in order to improve the rolling bearing product quality.
2 Cleanliness
2.1 Problems
(1) Before closing sleeve bearing parts cleaning is not clean.
(2) After closing sets, bearing cleaning is not clean to be oiled and packaging.
(3) oil lubricant rust with poor quality.
(4) assembly site in poor conditions.
2.2 improvements
(1) bearing rings, rolling elements (including seals, washers, etc.) After final inspection, close the front cover should be carefully cleaned.
(2) After closing sets strict control of finished cleaning time should be twice the cleaning, the cleaning solution to carry out a filtered and changed frequently.
(3) The application of high quality grease.
(4) to improve library and assembled on-site environmental finished.
3 residual magnetism
3.1 Problems
(1) finished parts to be assembled without demagnetization.
(2) No further cover after closing demagnetization demagnetization or incomplete.
(3) Demagnetization power is not enough.
Improper (4) Method demagnetization.
(5) Products from the field after the demagnetization storage sites too.
(6) Measuring instruments and measuring residual magnetism of the table itself with magnetic rivet.
3.2 improvements
(1) bearing parts before assembly to all demagnetization.
(2) should be fully co-sleeve demagnetization, demagnetization of the major product after repeatedly demagnetization.
(3) check whether the amount of residual magnetism meet the standard requirements, demagnetization machine power should be matched with the products.
(4) The workpiece demagnetization, demagnetization machine need to leave a certain distance (at least one meter or more), and then close the demagnetization machine.
(5) Withdrawal had to stay away from magnetic products demagnetization machine display.
(6) Periodic table of measuring instruments, adjust the instrument with the tools and rivets demagnetization, and optional residual magnetic tester.
4 clearance
4.1 Problems
(1) the reference member pass clearance is not uniform.
(2) Adjusting the clearance, improper operation, the measurement error is large.
4.2 improvements
(1) shall be in the Department of Mechanical metering central station (hereinafter referred to as metering central station) to transfer the oil industry bandgap reference piece unified.
(2) Measurement central station stages of the industry backlash instrument operator training, uniform measuring methods to reduce measurement error.
5, the surface roughness of the rolling parts
5.1 Problems
(1) most of the rolling surface roughness failed.
(2) ultra-precision ferrule raceway uneven.
5.2 improvements
(1) Small plants should strengthen the parts of the surface roughness of quality inspection, adding to the surface roughness testing equipment.
(2) on the part of super-finishing after sampling should be carried out before the ferrule assembly, the rolling surface roughness to one hundred percent inspection.
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6, parts of the surface burns
6.1 Problems
(1) Cut more than excessive, turning grain rough, deep, resulting in grinding infeed amount, causing secondary tempering burns.
(2) Wheel inappropriate choice.
(3) grinding inadequate cooling or coolant deterioration.
(4) wheel speed selection unreasonable.
6.2 improvements
(1) to strictly control the car, grinding allowance, and the appropriate choice of process parameters for processing.
(2) should be the right choice wheel.
(3) grinding coolant to the full, and the cooling liquid must be cast on a surface to be machined. Choose a suitable cooling liquid, and changed frequently.
(4) Select the appropriate wheel speed.
7, vibration
7.1 Problems
(1) of the ferrule groove (rolling) track and rolling the part geometry accuracy, surface roughness and waviness high.
(2) the ferrule cleaning is not clean, dirty oil.
(3) supporting the ball low accuracy.
(4) the reference vibration transfer member is not uniform.
7.2 improvements
(1) improve the precision of the bearing rings channel roundness, waviness, roughness and trench type deviation;
(2) to strengthen co-sleeve before cleaning parts, sealed bearings filled with low noise grease.
(3) improve the geometry precision ball bearing parts, reducing the parts work surface roughness and waviness.
(4) measurement of the central station should pay close attention to industry benchmarks vibration transfer member.
8, appearance quality
8.1 Problems
(1) The clash injured phenomenon more.
(2) mounting chamfer irregular.
(3) supporting jig centerless grinding obvious signs.
(4) bearing a trademark symbol unclear.
8.2 improvements
(1) increase workers' ownership attitude and quality consciousness, strengthening civilized production.
(2) the development of technology and production process strictly according to GB274-2000 bearing chamfer limit standards.
(3) After the bearing outer end of all processing steps, increasing the outer diameter of a repair research process, to eliminate residual traces of the outer diameter, improves the surface quality.
(4) Mechanical print prefix should be clear, the word deep to meet the requirements after the plane grinding to conduct sampling appearance, electrolytic marking the writing should be clear.
9, packaging quality
9.1 Problems
(1) poor quality of packaging materials, oil easily soaked wrapping paper.
(2) the failure to require procedures for packaging.
(3) the outer surface is not smooth, not clean.
9.2 improvements
(1) First, to enhance the quality awareness of product packaging, choose the appropriate packaging materials, to roll good wrap.
(2) should be required to program packaging, which is to use moisture-proof paper, then plastic sheeting packaging.
