Bearings Inspection
Find worn bearings without disassembly: sweep each head and the crossbar by hand, compare the two heads, mark the idler rollers to see if they spin, then remove the belts only if a check fails.
This guide explains how to inspect bearings and motion system components to identify wear, damage, or misalignment. Regular bearing inspection helps prevent layer shifting, noise issues, and mechanical failures.
The inspection has two levels:
- Quick checks - done by hand with the belts in place. They take a few minutes and catch most critical failures that affect printing: a seized idler, a binding head, a damaged motor bearing.
- Direct inspection - done with the belts removed. Do this only if a quick check reveals a problem and you need to find the exact bearing that causes it.
Before you begin - safety and risk
Read the Safety - Before You Begin article to understand the hazards involved in working on the Vision Miner 22IDEX V4 - including electrical, thermal, mechanical, and chemical risks. All procedures in this wiki are provided as recommendations only. By choosing to follow any procedure, you do so at your own risk.
Allow printer to cool completely
Do not attempt this inspection immediately after printing. Hot printer parts can cause injuries. Ensure the printer is cooled to room temperature before beginning.
Tools and Materials
- Permanent marker (for the idler roller check)
- Phone to record a video of the checks (recommended if you plan to contact support)
- Belt removal tools (only if performing direct bearing inspection) - see Belt Removal Instruction
Understanding Your Printer's Motion System
Your machine consists of four axis:
- X-Axis: Moves left and right (perpendicular to the machine) for the left head
Tool 0. It's driven by a belt and has its own motor on the back left side of the machine. - U-Axis: Another carriage, moves left and right (perpendicular to the machine) for the right head
Tool 1. It operates independently with its own belt and motor on the back right side of the machine. - Y-Axis: Moves forward and backward. It uses two belts and two motors located on opposite back corners.
- Z-Axis: Moves vertically, driven by three lead screws with motors under the printer floor.
Bearings Involved in Each Axis
There are three pairs of bearings involved in Y-axis movements, six in total:
- Two on the motors (horizontal ones on the back side of the printer, one on each side)
- Two working as idlers in the tension rollers (one in each front corner)
- Two flat ones on both sides of the crossbar, where the crossbar rides on the side rails
There are six bearings involved in X (U) axis movements for each head:
- One on the motor (vertical one on the back side of the printer, from the head side)
- One in the tension roller (front corner on the motor side)
- One at the printing head (flat one on the crossbar)
- Two idler rollers under the crossbar, from the head side
- One idler roller over the crossbar, on the side opposite to the head
Preparations
Power Off the Machine
- Cool down printer to room temperature.
- Turn off the printer and disconnect the power cord from the socket.
- Open the printer lid.
Record a video
If you are troubleshooting a problem together with our support team, set up your phone to record the checks below. A video of the head sticking, a roller not spinning, or a wobbling pulley tells support far more than a written description.
Check Belts First
Before proceeding with further operations, isolate potential issues by excluding belt problems:
- First of all make sure to tighten and tension the belt correctly according to the Belt Tensioning Manual. Lack of tension can cause layer shifting. Overtensioning can lead to fast bearing wear.
- Move the heads together to the far side of the printer and inspect all belts. They should be clean on both sides and free from wear, especially on the toothed side.
- Move the printer heads to the front side and repeat the inspection to check new sections of the belts after movement.
Quick Checks Without Removing Belts
Do the checks in this order. Each one isolates a different group of bearings, so by the end you will know whether the problem is in a head, in the crossbar, or in the Y-axis.
Maintain proper movement speed
To avoid static friction influence, the movement speed should be more than two inches per second but not more than ten inches per second to avoid circuit overloading.
Check 1: Each Head Along the Crossbar
This check involves the X (U) axis bearings only. The key is to compare the two heads against each other: they are identical, so a bad head feels noticeably different from the good one.
- Move the crossbar to the center of the printer.
- Move the right head (
Tool 1) all the way to the right end of the crossbar, out of the way. - Take the left head (
Tool 0) by the back side and move it along the crossbar over its full range, from the left end to the right end and back, several times.
- Feel and listen for sticking points, notchy movement, grinding, or squeaks. Note where along the crossbar it happens.
- Park the left head at the left end and repeat steps 3-4 with the right head.
- Compare the two heads. If one head moves smoothly and the other sticks or feels rough anywhere in its range, the problem is in that head's bearings, idler rollers, or belt path.
Check 2: Crossbar Without Holding the Belts
This check involves the Y-axis bearings and the flat bearings under the heads.
- Move both heads close to each other near the center of the crossbar.
- Take the crossbar itself, not the heads, and move it back and forth over its full range. Do not hold the belts.
- Watch the heads. Because the X and U belts are free, both heads must travel diagonally at 45 degrees - from the back left toward the front right as the crossbar moves forward, and back again as it moves backward.
- Pass: both heads follow the same straight diagonal and the crossbar moves smoothly. Fail: one head lags, stops, or moves along a different path than the other, or the crossbar sticks. A head that does not follow the diagonal has something binding in its belt path - an idler roller, the tensioner, or the motor pulley.
Check 3: Crossbar With the Belts Held
This check adds the X (U) axis motor, tensioner, and idler bearings to the Y-axis movement, so the heads stay in place while the crossbar moves.
- Keep the heads near the center of the crossbar.
- Pinch the X and U belts from below with your fingers so they cannot run, and move the crossbar back and forth over its full range.
- Feel and listen for sticking, grinding, or squeaks. If Check 2 was smooth but Check 3 is not, the problem is in the X (U) belt path that was bypassed in Check 2: the motor bearing, the tensioner, or the idler rollers.
Check 4: Idler Rollers on the Crossbar (Marker Test)
Each head runs over three idler rollers on the crossbar: two under it and one over it. A roller with a seized bearing does not spin, and the belt drags across it. This is easy to miss by feel but easy to see with a marker.
- Put a short line with a permanent marker on the visible edge of every idler roller on the crossbar, for both heads.
- Move each head along the crossbar over its full range.
- Check that every marker line has moved. A line that stays in the same place means that roller is not spinning and its bearing is seized or badly worn.
Check 5: Belt Tensioner Bearings
The tensioner roller is toothed and the bearing sits inside it, so you cannot see it turn or mark it like the crossbar idlers. The only way to check it without disassembly is to listen: pinch the belt near the tensioner so the roller itself stays still relative to your hand, move the axis, and listen right at the tensioner for any sound that does not belong there.
The bearings in the belt tensioners are very small and they seize more easily than the others. Usually they start with a squeak. If a squeak is ignored, the bearing eventually locks up and the belt grinds over a roller that no longer turns.
- For the Y-axis tensioners, pinch each Y belt near its front-corner tensioner and move the crossbar back and forth over its full range (as in Check 3), listening closely at that corner.
- For each head's tensioner, pinch the X or U belt near the tensioner and move that head over its full range, listening closely at the tensioner.
- A squeak from a tensioner is an early warning - check it before it seizes. A grinding or rattling sound means the bearing is already damaged.
Check 6: Motor Pulleys
- Open the rear door of the printer. The four motors are in the back: the two Y-axis motors in the back corners and the two tool motors, X on the left and U on the right. See the rear overview in Failing Motor Diagnostics if you are not sure which motor is which.
- Look at the pulley of the motor for the axis that failed a check above.
- Have someone move the axis by hand while you watch the pulley. It should turn smoothly and without wobble, and the belt should sit centered on it and not rub against the pulley flanges.
Signals Indicating Bearing Issues
Listen for sounds produced by belts, tensioners, idlers, and motors. Look at motor and tensioners while moving. Pay attention to:
- Grinding sounds - bearing probably damaged.
- Squeaks sounds - bearing damaged and/or belt misalignment. From a tensioner, this is an early sign that its bearing is about to seize.
- Clicking sounds - bearing damaged and/or belt misalignment.
- Sticking points - bearing damaged, dust on the rails, lack of lubrication, crossbar and rails misalignment.
- One head moves noticeably worse than the other - bearing or idler roller damaged on that head.
- Heads do not follow the 45 degree diagonal in Check 2 - something binding in the belt path of the head that lags.
- Marker line on a roller does not move - that roller's bearing is seized.
- Variable sound frequency with a constant moving speed - motor bearing probably damaged.
- Visual roller or pulley oscillation - bearing damaged.
- Excessive black dust accumulated on the build plate or on the belt tensioners - belt is grinding heavily against the belt tensioner due to misalignment. Potentially tensioner or motor bearing is damaged. (Note: small amounts of black dust from normal belt wear are acceptable.)
If any of the quick checks shows one of these signals, proceed to the direct bearing inspection below to find the exact bearing. If all quick checks pass, the motion system bearings are unlikely to be the cause of your problem.
Direct Bearing Inspection
With the belts removed, every bearing can be turned on its own, so a bad one can no longer hide behind the others.
- Remove belts: Follow the Belt Removal Instruction.
- Inspect the Belt Tensioners:
- Remove each tensioner from its holder.
- Check Rotation: Roll it with your finger to ensure it rotates smoothly without resistance. The bearing is small, so even slight roughness or a rotation that stops early is a sign of wear.
- Inspect the Idler Rollers on the Crossbar:
- Spin each of the three rollers for each head with your finger.
- Check Rotation: Each roller should spin freely and coast for a moment. A roller that stops immediately, feels gritty, or does not turn at all needs replacement. See Crossbar Bearing Replacement.
- Inspect the Motors:
- Access the motor from the back of the machine.
- Check Rotation: Rotate the motor pulley with your finger or use a belt to turn it.
- Smooth Operation: It should rotate smoothly without any grinding noises. Motors are sealed: if the bearing is bad, replace the motor. See Failing Motor Diagnostics.
- Inspect the Flat Bearings:
- Move the head along the crossbar or the crossbar along the rails for the entire operational distance.
- Check Movement: It should slide smoothly without any grinding noises.
- Check for Stuck Points: Sometimes it can stick a bit and continue moving without much power, but it should not stick at the same point several times in a row or require too much power to move.
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