metal slitting machine line

what factors produced BURR in steel slitting?

Burr formation in Rotary steel slitting:

Rotary steel slitting is now widely used for distributing a wide strip into a some of the narrow strips or for modification wide sheet metal stock. However, with a conventional slitting process, burr formation on the slit edge is inevitable.

Burr formation is a common sheet metal defect and Burr control / deburring is an important issue for industrialist and engineers. It is produced in all shearing & cutting operations. In sheet metal parts burr is usual but after a specified limit, it takes a form of defect. This leads to rework and the quality problem of a part. So controlling this defect is the issue of quality as well.

This post describes what are the possible causes & how can we prevent it. Except die & punch clearances, there are still many factors which affect the burr formation.

As all the sheet metal industries are heavily affected by the burr problem, indicating the study of all the possible causes and remedies. This paper also clears that what practices can increase the tool life & how long we produce “burr-free” parts. It includes the selection of the best materials and methods for „press tools‟, „tool

BURR IN STEEL SLITTING

BURR IN STEEL SLITTING

Study of all factors causing BURR

Sheet metal parts play an important role in the automotive industry. Different types of reinforcement, body parts, and door parts are manufactured in sheet metal scope. With every manufacturing process, there are some defects associated with the same. In the same manner in sheet metal components there are also many types of defects arises in different processes. But out of these defects, the most common and prominent defect is a burr. This defect has no.of cost-effective impacts as follows.

  1. Adding unnecessary processes i.e. rework
  2. Production loss
  3. Quality issues
  4. Risk of a defect being passed to “customer”
  5. Affecting 5-S

Application of sheet metal components includes Aircraft industry, Automobiles, Construction work and many other applications such as appliances.

Causes of Defects Burr In Sheet Metal

Identify Cause  /Reason  /Countermeasure

Identify Cause: Operator awareness

Reason: The operator is not locating the part in specified location gauge. Feeding of double

parts/sheets which can damage the sharp edge of die and punch. This leads to burr formation.

Countermeasure: Training has to be provided

Identify Cause: Skill of Operator

Reason: The operator should be capable to grasp the given training. Due to the absence of skill, he will repeat the mistake thus it increases the chance of an accident.

Countermeasure: The operator should be according to process criticality

steel Slitting-burr

steel Slitting-burr

what factors produced BURR in steel slitting?

Identify Cause: Raw material grade & thickness

Reason: Due to die & punch clearance is dependent on raw material thickness. So it is important to feed actual sheet thickness material. If we select a sheet having less thickness from actual then in this condition clearance between die & punch will be more and at the time of cutting proper shearing & breakage will not be produced. Thus burr will be formed. As well if we will use higher sheet thicknesses then less clearance will be maintained or no clearance thus cutting process will be interrupted and heavy accident will go on.

Countermeasure: Proper control on raw material should be taken place by the RI department. Also, quality & production supervisors should be ensuring about the RM before feeding in a tool. For proper implementation of the above idea, this should be converting into a system.

Identify Cause: Part handling

Reason: The method is directly related with Man i.e. operator

resource. In absence of proper handling or part loading method into the tool may cause of burr. Sometimes part trim/edge get damage due to unsafe part handling or movement.

Countermeasure: An operator should be sufficiently trained

 

 

 

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Stainless Steel High Precision Slitting Line

LOTOS SOLUTIONS FOR STEEL SLITTING PROBLEMS:

STEEL SLITTING PROBLEMS include; edge waves, crossbow, knife marks, burrs, camber, and inconsistent slit widths. some of these issues may be creat by poor material quality, but more often caused by disorders which happen in the system during the coil slitting process. LOTOSFORMING discuss slitting problems and present solutions to reduce possible problems.

PROBLEM      /   POSSIBLE CAUSE

What arises Problems during metal slitting?

How to avoid slit-in coil slitting problems?

Many issues can happen in steel slittings such as poor edge quality, edge burr, edge wave, camber, crossbow, knife marks, and slit width.

  • Too much BURR generated from slit process
  1. Too Much side pressure
  2. Wrong main shaft angle
  3. Excessive blade penetration
  4. Dull or incorrectly resharpened blades
  5. Slitter shaft vibration in high speed

Burr is an edge fault that accrues during slitting. The primary cause of burr is a horizontal knife clearance that is very tight or very weak. A wrong clearance spontaneously causes a poor-quality edge. In fact, one of the specifications of a poor-quality edge is a burr.

  • Top knives chipping
  1. Too Much side pressure
  2. Too little blade overlap
  3. Radial runout in the top knife
  4. Top knife jumping out during operation

Extensions to the COIL STEEL SLITTING PROBLEMS :

  • Blade life too short
  1. Blade incorrectly resharpened (burred cutting edges – heavy burrs)
  2. Excessive blade penetration too deep – too shallow
  3. Too much side pressure
  4. Excessive cant angle
  5. Radial runout
  6. Axial runout or wobbling in lower knife

 

  • Ragged edge on ONE side of steel strips
  1. Cant angle much too steep
  2. Blade penetration too deep
  3. Blade cutting angle incorrectly selected and/or sharpened

 

  • Ragged edge on both sides of a cut
  1. Blade angle incorrectly selected
  2. Cant angle much too steep
  3. Blade penetration too deep
  4. Blade cutting angle incorrectly selected and/or sharpened
  5. Incorrect offset
  6. Radial runout
  7. Heavy vibration at high speed

 

PROBLEM THAT OCCURS IN METAL SLITTING?

  • Scallop slit line
  1. Axial runout on lower knife

 

  • Web folds between blades are not cut
  1. Negative cant angle
  2. Blades improperly reground
  3. Side pressure too light

 

  • Tearing of web  at a cut point
  1. Incorrect trim removal
  2. Blade penetration too deep. Web not truly tangent to the top point of a bottom knife

 

All you need to know about Solve Steel Slitting Problems :

  • Interrupted slitting
  1. Nicked or damaged cutting blades
  2. Radial runout of either top knife or bottom knife or both
  3. Side pressure too light

 

  • Web breaks
  1. Nick on any edge of a knife (usually a top knife)
  2. Web tensions too high
  3. Web not truly tangent
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