Troubleshooting Timing Belt Problems

Troubleshooting Timing Belt Problems

Timing belts play a critical role in the operation of precision machinery, ensuring the seamless coordination of various components within a drive system. However, despite their seemingly simple design, timing belts are susceptible to a range of issues that can lead to failure, causing disruptions and potentially costly damages. When timing belts are used within the limits of their specifications, they will provide long and efficient service life. However, there are external forces and issues that will cause belt failure. The vast majority of these failures are fixable, or even avoidable. Consulting with a timing belt expert with ensure that failure is not a option.

Below, we will explore the most common types of  timing belt failures, exploring the root causes, potential consequences, and most importantly, the corrective actions to keep your machinery ticking with precision. From the subtleties of temperature-related issues to the complexities of misalignment and tension irregularities, our guide aims to demystify the common problems associated with timing belts.

Timing Belt Tooth Shear

Issue: Timing belt teeth are coming away from the belt base

Problem Solution
Misaligned drive check pulleys for proper alignment
Mismatched timing belt and pulley Be sure you are using a pulley of the same pitch as your timing belt
Timing belt pretention may be too low Determine the proper pretension for your belt pitch and width and adjust accordingly.
Pulley diameter is too small Switch to a pulley with more teeth. Be sure your pulleys are properly sized for your drive.
Excessive load Adjust your drive with a stronger, larger timing belt and components that can handle the load.
Back bending idler is slipping Change to an inside idler.

Tensile Failure

Issue: The timing belt has snapped

Problem Solution
Excessive load Adjust load or change drive to accomodate load
Extreme belt overtensining This would be avoidable with proper pretension. Replace belt
Misalignment Adjust pulleys for proper alignment and change belt
Debris in drive Keep drive free of particulate.
Excessive load Adjust your drive with a stronger, larger timing belt and components that can handle the load.
Back bending idler is slipping Change to an inside idler.

Timing Belt Running Hot

Issue: Timing belt is getting hot even though they are in an ambient environment

Problem Solution
Misaligned drive Check parallel and angular alignment of timing belt pulleys
Improper Pretension Utilize the SM5 Tension meter and phone app to calculate and set proper pretension
Timing belt tooth profile and pulley are not a perfect match Verify the pitch of both the timing belt and pulley. Using BRECOflex components together guarantees perfect meshing

Timing Issues in a High Precision Drive

Issue: Backlash is causing in error in precision

Problem Solution
Settling time isn’t fast enough Switch to a stiffer timing belt such as move-series
Timing belt has too much play in the pulley Switch to a zero backlash pulley

Belt Edges are Wearing

Issue: The belt edges are wearing causing damage to the belt or exposing tension members

Problem Solution
Improper Tracking Check the alignment of the pulleys
Timing belt is hitting an obstruction or blemish on the pulley flange Repair the flange or replace with a new flange
Timing belt is too wide for the pulley Replace with properly fitting components.
Improper pretension Adjust to proper pretension using the SM5 tension meter.
Timing belt is scraping along the drive guard Consider replacing belt with a self-tracking version.

Timing Belt is not Tracking Properly

Issue: The timing belt is not tracking straight.

Problem Solution
Belt edge wear Check pulley alignment. See section on edge wear
Weak support structure Reinforce with a slider bed
Pulley has not flange Switch to pulleys with flanges or a self-tracking timing belt.

Timing Belt Noise is Excessive

Issue: The timing belt drive is very noisy under normal operating conditions. See more on causes of belt noise

Problem Solution
Impact of the belt teeth on the pulley minimize the polygonal effect with continuous tooth engagement. Reduce the belt width or used a lower tooth. Use a coated belt such as move-series
Air Displacement by the teeth on the pulley Use multiple smaller belts. Cut air grooves in the pulley
Friction between the belt and the pulley Try PAZ to minimize friction on the tooth side. Try a dry lube or silicone grease. Check pulley and belt sizing for meshing issues. Switch to a BAT/BATK belt which reduces friction and vents air toward the belt edges, reducing noise
Resonance frequencies change driving RPM. Use a belt like ARC Power to reduce polygonal effect.

Cracks in the Belt

Issue: cracks are forming in the polyurethane timing belt or belt backing

Problem Solution
Temperature too high Maintain an environment between 32F - 176F
Temperature too low Maintain an environment between 32F - 176F
Exposure to incompatible chemicals Reference the Chemical Resistance Chart
Pulley diameter too small Increase pulley diameter/tooth count

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