Fault Finding With Bandsaw Blades

Blead Breakage

Straight break indicates failure

Probable Cause

• Incorrect blade – teeth too coarse
• Band tension too high
• Excessive feed
• Incorrect cutting fluid
• Wheel diameter too small for blade
• Teeth in contact with work before start saw
• Guides too tight

Solution

• Use finer tooth pitch
• Reduce band tension. See machine operator’s manual
• Reduce feed pressure
• Check coolant
• Use thinner blade and lower speed
• Adjust wheel alignment
• Allow 1/2″ clearance before starting cut
• See operator’s manual

Premature dulling of teeth

Probable Cause

• Blade teeth inverted (backwards)
• Improper break-in period
• Hard spots in material (like scale)
• Material work hardened (check for hardness and adjust feed)
• Improper cutting fluid or mixture
• Speed and feed too high

Solution

• Install blade correctly
• Reduce feeds and speeds during break-in period in accordance with manufacturer’s recommendations
• Check material for actual hardness-hard spots like scale or flame cut surfaces
• Increase feed pressure
• Check coolant
• Check recommendation chart

Inaccurate cut

Probable Cause

• Teeth dull
• Over or under feed
• Improper pitch blade
• Incorrect blade (too many teeth per inch)
• Cutting fluid not applied evenly

Solution

• Use new blade
• Check recommendation chart
• Adjust coolant nozzles
• Tighten or replace guides

Leading in cut

Probable Cause

• Over feed
• Lack of band tension
• Tooth set damage
• Loose guide arms or set too far from work

Solution

• Check recommendation chart
• Check operator’s manual for correct tension
• Check material hardness
• Adjust arm close to work as possible, tighten and align
• Check machine guide

Chip Welding

Probable Cause

• Improper or lack of cutting fluid
• Wrong coolant concentration
• Excessive speed or pressure
• Incorrect blade (wrong pitch)

Solution

• Check coolant
• Reduce speed or pressure
• Check recommendation chart

Teeth fracture

back of tooth indicates work spinning in clamps

Probable Cause

• Incorrect feed and/or speed
• Incorrect blae (wrong pitch)
• Saw guides not adjusted properly

Solution

• Check recommendation chart
• Adjust or replace saw guides

Irregular break

Indicates material movement

Probable Cause

• Indexing out of sequence
• Material loose in vice

Solution

• Check for correct indexing sequence (head rise)
• Check hydraulic pressure

Teeth stripping

Probable Cause

• Feed pressure too high
• Tooth stuck in cut
• No cuttig fluid or incorrect coolant
• Hard spots scale, inclusions, etc
• Incorrect blade (wrong pitch)
• Work spinning in vice; loose “nest” or bundles
• Blade teeth running backwards

Solution

• Reduce feed pressure, see recommendation chart
• Never enter same (old blade) cut with new blade
• Check coolant table
• Check hardness. Descale and or anneal if necessary
• Check recommendation chart
• Check hydraulic pressure; be sure work is firmly held
• Reverse blade (turn inside out)

Wear on back of blades

Probable Cause

• Insufficient blade tension
• Back-up guide frozen in position, damaged or worn
• Guide arms to far apart, worn or loose
• Blade rubbing on wheel flanges

Solution

• See machine operator’s manual for correct band tension
• Reduce feed pressure, see recommendation chart
• Free pressure block and realign. If worn replace (never regrind)
• Move arms close to work as possible
• Adjust wheel alignment

Rough cut

Washboard surface vibration and/or chatter

Probable Cause

• Dull or damaged blade
• Incorrect feed and/or speed
• Lack of band support
• Insufficient band tension
• Incorrect pitch blade

Solution

• Replace with new blade
• Check recommendation chart: adjust until noise disappears
• Set guide arm properly – as close to work as possible
• Check operator’s manual for correct tensions

Wear lines, loss of set

Probable Cause

• Saw guide inserts or pulley on teeth
• Insufficient blade tension
• Hard spots
• Backing guide worn

Solution

• Check operator’s manual for correct blade with
• Check for correct blade tension
• Check material hardness
• Replace

Twisted blade

Profile sawing

Probable Cause

• Band sticking in cut
• Side guides adjusted too tight
• Work not held firmly
• Incorrect or lack of cutting fluid

Solution

• Check for over-feed, damage set, is blade too wide for radii being cut?
• Set side guides properly
• Check vice and hydraulics
• Check coolant

Blade wear

Teeth blued

Probable Cause

• Incorrect blade
• Incorrect lead or speed
• Improper or lack of cutting fluid

Solution

• Check recommendation chart
• Check coolant

Broken teeth

Front of tooth indicates work spinning in vice

Probable Cause

• Material loose in vice
• Incorrect blade (wrong pitch)

Solution

• Check hydraulic pressure
• Check recommendation chart