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Case study that the bearing rubs process technology and trace or burns


31st July 2013 Bearing Technology 0 Comments

The case study that the bearing rubs process technology and trace or burns:

The work piece appearance is reproduced and will often be burnt in grinding to burn the surface of the trace work piece, burn several kinds of types, first, burn in the direction that the emery wheel is processed, black dull plaque; Second, take the form of the lines or lines of make-and-break.

The surface of the work piece is burnt in the course of rubing and processing, sum up and have the following reasons:

1.The emery wheel is too hard or too detailed organization of graininess is too dense;

2.The feeding amount is too big, cutting fluid is insufficient in supply, the heat-dissipating condition is bad;

3.The work piece is overlow in rotational speed, the emery wheel is too fast in rotational speed;

4.The oscillate of the emery wheel is too big, burn because the grinding depth changes frequently;

5.The emery wheel is not repaired in time or not repaired well;

6.The adamas is sharp, the emery wheel is not repaired well;

7.It is too deep to burn at the time of the rough grinding of the work piece, it is too small to finish grind the allowance, has not ground off;

8.The work piece clamping force or suction is insufficient, under the strength function of grinding, the work piece stalls phenomena,etc..

Then how does the surface of work piece know whether to burn the affair in grinding? This can be checked in through fixed acid cleaning.

After the acid cleaning of the work piece, when appearance is wet, should estimate under the astigmatism light and examine immediately, look, take the form of even and dark and gray normally. If clicked by the software, cloud dark black speckle appear, and perimeter is indefinite and whole; {HotTag} If decarbonizate, it is piebald to appear ashen or black dull; If rub, process crackle, crackle full of cracks in shape then, burn in this way, first, appearance appear black dull plaque in the direction that the emery wheel is processed, second, the lines or lines of make-and-break appear. Present, burn the phenomenon while being above-mentioned in the course of rubing and processing, must analyze the reason in time, take the effective measure to solve, stop to burn in batches.

Appearance degree of roughness reach, require the intersection of bearing and the intersection of appearance and degree of roughness of part have norm and technological requirement, but because of various reasons in the course of rubing and processing and ultra and precise, can not often reach the specified requirement.

Lead to the fact the unqualified major cause of degree of roughness of the work piece appearance is

1.Grinding is overlow in speed, the feed velocity is too fast, feed and measure too big, it is too short not to feed the time of grinding;

2.The work piece is too high in rotational speed or work piece axle and emery wheel axle are shaken too big;

3.The emery wheel is too thick or too soft in graininess;

4.It is too fast or repairs the interval of organization too big to repair the speed the emery wheel;

5.The adamas which is repaired the emery wheel is not sharp or quality is not good;

6.Ultra to use the intersection of whet stone and quality to be good while being precise, device position incorrect;

7.Can’t meet the quality requirement ultraly and smartly with the kerosene;

8.Extremely precise time is too short,etc..

The bearing is in the course of rubing and processing, what carried on grinding through the revolutionary emery wheel of the high speed on its surface of job if does not carry on operating and control equipment according to the homework guide book during grinding, will appearance appears all sorts of defects, so that influence the global quality of the bearing in work by bearing.

The bearing, during accurate grinding, because coarse to expect very much, grinding trace that working appearance presents can observe frequently the grinding trace of it appearance has the following aspects mainly with the naked eye.

Appearance appear, cross the intersection of helical line and trace appear the reason of trace because bus wire of emery wheel flat and straightforward and poor mainly, the unevenness phenomenon exists, at the time of grinding, emery wheel and work piece are contacted by the part, after several back-and-forth movements of work piece or emery wheel, the work piece shows that will reproduce and cross the helical line and can observe the spiral collinear thread pitch and a speed, rotational speed of work piece of work piece are relevant in magnitude with naked eye, not parallel and relevant with shaft axis and work bench guide rail of emery wheel at the same time.

One Formative major cause of helical line

1.It is bad to repair the emery wheel, the corner has not chamfered, has not used the cooling fluid to repair;

2.Work bench guide rail lead lubricating oil to be too much, cause the work bench to float;

3.The lathe is not good in precision;

4.Squeezing action of grinding,etc..

Two Helical line formative to have reasons

1. good in stiffness in Vee way,when grinding deflect emery wheel, but keep in touch emery wheel edge as appearances working; 2.The communtation of the work bench is unstable in speed while repairing the noisy wheel, the precision is not high, make a certain edges of emery wheel slightly repaired little; 3.One’s own stiffness of the work piece is bad;

4.Break the scale specking under sand grain and work piece grinding peeling off very much to accumulate and attach to appearance of the emery wheel on the emery wheel, for this reason the emery wheel that should repair is washed or scrubed clean with the cooling water;

5.It is fine for emery wheel to repair, have some and protruding, etc.

Appearance presents the appearance of fish scale to reproduce major cause of the trace of the fish scale because the cutting edge of the emery wheel is not sharp enough, happen at the time of grinding ” Gnaw ” The phenomenon, it is relatively great to shake at this moment.

Lead to the fact the work piece appearance presents the fish scale the concrete reason of the trace is

1.The appearance of the emery wheel has rubbish and oil dirt;

2.The emery wheel has not repaired the round; Bearing knowledge

3.The emery wheel is dulled. Do not repair sharply enough;

4.The adamas fastens a insecure, the adamas is waved or the adamas quality is not very sharp;

5.The emery wheel is heterogeneous in hardness,etc.. The working face gigs the major cause why appearance reproduces trace of gigging takes off the backwardness because of the abrasive grain of thick graininess, {TodayHot} The abrasive grain is inserted to cause between work piece and emery wheel.

The concrete reason why the surface of the work piece is gigged during grinding is

1.The trace left over at the time of rough grinding, has not ground off while finishing grind;

2.Thick abrasive grain and minification abrasive grain can not be filtered clean in the cooling fluid;

3.The abrasive grain was easy to loss when the thick graininess emery wheel was just repaired well;

4.The toughness effective date of materials or emery wheel is too soft;

5.Abrasive grain toughness cooperates with work piece materials toughness improperly etc.

Work piece appearance have undulate trace hang down the shaft axis, cut first cross profile and enlarge work piece that rub direct, can see its circumference is similar to the sine wave. Make its centre not rotate and translate along the shaft axis, the perimetral orbit of sine wave is an undulate prismatic face, also call this the polygon. So. This kind of vibration may be forced vibration, and may be the self-excited oscillation too, so the straight wave on the work piece is often more than one kind frequently.

The concrete reason of the undulate trace is directly to take place

1.The basic shaft interval of emery wheel is too big;

2.The emery wheel is too tall in hardness;

3.The static balance of the emery wheel is not good or the emery wheel is dulled;

4.The work piece is too high in rotational speed;

5.The horizontal Qi’s knife is too large;

6.The basic shaft bearing wear of the emery wheel, it is too big to cooperate with the interval, diameter run-out takes place;

7.The emery wheel cramp the organization or work benches ” Creep ” When.










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