📩 Customer Support Response
Customer writes:
"Hi, I found a small issue with my polystyrene cutting machine, on both the vertical and horizontal axes. When I cut, it comes out a bit crooked. The two guides go parallel for a while, then after some time both axes seem to skip some teeth. The cut ends up diagonal instead of straight. Also, when the machine moves, I notice the front wheels are more to the left than the rear wheels. Can you help me solve this? Thanks!"
✅ Technical Answer:
Hello! Your description is perfect: this is the classic symptom of synchronism loss between the two sides of the machine. The dry "click" you hear is the belt jumping over a pulley tooth, and the misalignment between front and rear wheels confirms it.
Here's the quick fix procedure (valid for both HORIZONTAL and VERTICAL axes):
- Check pulley grub screws – Make sure the two small black hex grub screws on the aluminum pulleys are tight. If loose, the shaft spins freely inside the pulley.
- Mechanical clearance (most common cause) – On both ends of the machine, check that there is a small gap (1-2 mm) between the toothed head and the side metal plate. If they touch, the belt jumps → loosen screws, create clearance, retighten.
- Belt tension – If you hear the "click" and see the belt jump over the teeth, it's too loose. Tighten it slightly.
- Idler bearing – Make sure the belt passes over the round metal bearing, not to the side.
Follow the detailed steps below with the photos, and you'll solve it in 5 minutes! 💪
Problem Symptoms
If during polystyrene cutting you notice the wire cutting diagonally, the front wheels remain misaligned compared to the rear wheels, or you hear a dry metallic noise (a "click"), the machine is losing mechanical synchronism due to a belt tooth skip or pulley slippage.
Step-by-Step Resolution Procedure
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1 Check Pulley Grub Screws (Very Rare Case)
In very rare cases, the problem can be caused by the small black hex grub screws located on the aluminum collars of the pulleys connected to the threaded rods. If these screws loosen, the shaft spins freely inside the pulley, simulating a tooth skip. Although rare, it's advisable to check they are tight before proceeding with belt realignment.
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2 Check the Belts (Tension Check)
Observe the machine while it's moving: if you see the belt making a small jump over the gear teeth corresponding to the "click", it means it's too loose or encountering an obstacle. Visually check that there are no plastic burrs or polystyrene buildup along the path. If everything is clean, try tightening the belt slightly to prevent skipping.
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3 Check Mechanical Clearance (Both Rods and Ends)
Look carefully at the rod with the toothed head near the metal plate: this check must be performed rigorously on both rods and on both ends of the machine. There must always be a small gap (minimum visual play) between the metal plate and the toothed head. If there is no gap even on just one side, the head jams against the plate, creates a lot of friction, and stops, forcing the belt to skip teeth. Verify everything spins freely and also check that the black hex grub screws on the pulleys are tight.
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4 Check Belt on Bearing
Check that the belt passes correctly over the idler bearing. Sometimes, due to assembly error or if it slips out of its seat, the belt does not rest on the bearing. If it's in the wrong position, the belt will naturally remain loose and lose proper tension, eventually skipping teeth during operation. Make sure it's positioned correctly as shown in the photo.