So you have a pallet wrapper & the stretchwrap carriage keeps going up and you want it to stop doing that.
Our guide below will give you some things to try to get you pallet wrapper working properly again.
Please note: Some of these steps may need a qualified technician, don’t attempt all these yourself if they are out of your expertise.
Pallet wrapper height detection sensor
Modern Pallet wrappers are equipped with an infrared or logic sensor to identify the height of the goods. The Below are some of the issues where the sensor could cause the carriage to not detect the height of your goods properly:
- The sensor range is set too far & so it is seeing something in the background. Solution: Reduce sensor range
- Sensor is pointing down, so it is seeing the goods for too long. Solution: Adjust the angle to be level
- Sensor is getting too much light. Solution: Reduce light, adjust angle of sensor or machine to reduce direct sunlight
- The sensor is faulty, this usually involves the sensor being damaged somehow, and in many cases signs of damage to a sensor are visible. Solution: Replace sensor
- The cable attached to the sensor is loose. Solution: Try tightening the cable connection.
- Sensor has an issue with the cable attached to it. You may be able to see obvious signs of damage or the issue could involve a broken wire in the housing of the cable. This will need to be tested by a multimeter and requires a technician. Solution: Replace cable
Foot crush switch activated or faulty
Most pallet wrappers are equipped with an anti-foot crush switch under the carriage.
If that switch is hitting something, the crush plate is jammed, or the switch is jammed and engaged, what will happen on most wrappers is the carriage will go up 100mm-200mm then stop and go into error.
Here’s what you need to do when this happens:
- Check there is nothing under the carriage.
- Check the foot crush plate is not activating the foot crush switch, the plates on most wrappers should move somewhat freely up and down.
- Check the switch itself isn’t engaged because its jammed closed.
- If the machine is displaying a foot crush error, but you have checked all the above, the problem could be related to something else and it you may need to call a technician to replace a faulty switch or check the cables for continuality.
The machine is set for preset wrapping height
Some machines have a preset wrapping height mode (which may be taller than your pallet) and the carriage is maybe going to this height.
On an ALTANTA STRETCH machine this is FUNCTION 12. Function 12 should be set to “50” / “OFF” and then the machine will work with the photo logic sensor.
Other brands of machines may have a similar function, so it’s worth checking your user manual.
Pallet wrapper carriage belts are on backwards
Some cheaper model machines use belts instead of chains for carriage ascent. Belts sometimes have a habit of winding themselves on backwards.
If your machine uses belts, do the following:
- Switch the machine to manual mode
- Press carriage ascent button, if the carriage goes down instead of up the belts have winded themselves on backwards
- This is common on cheap machines which use belts instead of chains. The limit switch and foot crush device have likely failed, or the carriage is missing the bottom limit switch and then the foot crush device isn’t working properly.
- The belts will need to be unwound by using the manual controls and put back on using the manual controls. You may need a technician or maintenance staff to help with this step.
- If your belts did wind themselves on backwards, we would suggest looking at replacing the bottom limit switch, foot crush switch, or see why the machine is missing the bottom limit switch, as the bearing or rail maybe damaged.
We hope you found this guide on pallet wrappers helpful