CONTROLLED AUTOMATION, INC.

BEAMLINE TROUBLESHOOTING

FLANGE – SMALL GAUGE

 

When a beamline flange unit punches holes at a small gauge, the flange punch frame must position very close to the web of the material for both the near hole and the far hole. To position close to the web like this, everything on the flange probe measuring system and the flange frame itself, must be mechanically correct. The flange unit must also be calibrated very accurate.

In addition, punch dies with a machined flat outer section must be used (See Figure 1). With this type of die, the minimum gauge for the flange punch is approximately 1" plus 1/2 the thickness of the web. So for a normal 2-hole flange pattern, it is approximately 2" plus the thickness of the web. This is with the flat outer surface of the die being in contact with the web of the material.

Figure 1

With standard round dies, the minimum gauge for the flange punch is approximately 1-1/16" plus 1/2 the thickness of the web. For a normal 2-hole flange pattern, it is approximately 2-1/8" plus the thickness of the web. This is with the outer surface of the die being in contact with the web of the material.

These minimum gauges are calculated using the outside dimensions of the punch die. Usually there is something mechanically loose, out of adjustment, or the flange is not calibrated correctly. If the flange holes on a beam are off center from the web by 1/16" or 1/8" (shifted up or down on the flange), this may be within tolerance for certain jobs. But when punching small gauges, the flange frame must position so close to the web that this is not accurate enough.

For example, if a 3" gauge hole pattern on the flange are being punched off center of the web by 1/8", the actual gauge, from the center of the web, will be 1-5/8" for one punch while the actual gauge for the other punch will be 1-3/8". If the gauge of the hole pattern is smaller, one punch may be able to punch a hole (larger gauge) but the other will not (smaller gauge) because it will hit the web and still not be at the correct position. Which punch will get into position and punch depends on which way the hole pattern is shifted in respect to the center of the web.

 

Check the following mechanical and electrical parts of the flange probe assembly. Then check the calibration of the flange unit.

  1. Check the probe assembly mechanics (Loose nuts, bolts, springs, bent or worn guide rods, and bearings). Check the encoder gear, gear rack, etc.

  2. Make sure that both of the flange probe tips contact the web of the material the same (probe tips are level with each other). The flange probe tips must retract past the flange punch frame surface that will be near the web (See Figure 2 & 3). If they do not, this will limit the minimum gauge and possibly cause mechanical damage to the flange probe assembly.

Figure 2

 

Figure 3

C. Check the alignment of the encoder gear and the gear rack through entire length of travel for the probes. There should be a little slack (clearance) between the gear and the gear rack. The gear on the encoder should be able to turn slightly. If, at one end there is slack and the other end there is not (tight), chances are that the shaft of the encoder is being side loaded. This will cause the bearing in the encoder to fail. If there is too much slack, the measurements will be inconsistent and inaccurate. Any mechanical wear or movement in the probe assembly will cause inaccurate measurements.

 

D. Check that the probes fully extend and retract. If they do not, the machine may initialize the probes at the wrong position and cause incorrect measurement. Often dirt, grease, mill scale, and/or punch slugs will keep the probes from fully extending or retracting.