Guidebook
Raw materialManufacturingConvertingSanding methods Sanding faults: causes and actionsProduct recommendation1. Raw material1.1 Principles of the construction of coated abrasives
1. Raw material1.2. Backing material1.2.1. Paper1. Raw material1.2. Backing material 1.2.2. Cloth
1. Raw material1.3. 1st binder1.3.1. Animal glue1. Raw material1.3. 1st binder 1.3.2. Synthetic resin1. Raw material1.4. Grains1.4.1. Aluminium oxide1. Raw material1.4. Grains1.4.2. Silicon carbide1. Raw material1.4. Grains1.4.3. Grit sizes
1. Raw material1.4. Grains1.4.4. Grit sizes
1. Raw material
1. Raw material1.5. 2nd binder1.5.1. Synthetic resin1. Raw material1.6. Sanding active fillers1.6.1. Antistatic abrasives
1. Raw material1.6. Sanding active fillers1.6.2. Stearated abrasives
Raw materialManufacturingConvertingSanding methodsSanding faults: causes and actionsProduct recommendation
2. The manufacturing process 2. The manufacturing process 2.1. Raw material of paper or cloth
Raw materialManufacturingConvertingSanding methodsSanding faults: causes and actionsProduct recommendation
3. Converting3.1. Slitting of rolls3. Converting3.2. Cutting of material for endless belts3. Converting3.3. Joint skiving3. Converting3.4. Joint pressing
Raw materialManufacturingConvertingSanding methodsSanding faults: causes and actionsProduct recommendation
4 Sanding methods 4. Sanding methods 4.1. Calibration4.1.1. Description and recommendationsCalibrate to the right thickness.Chatter marks from planer, if any, are removed. Sanding machines equipped with sanding pads are not suitable for calibration. The efficiency of the stock removal is effected by the diameter and the hardness of the rollers.4. Sanding methods 4.1. Calibration4.1.2. Stock removal recommendations4. Sanding methods 4.2. Cross sanding4.2.1. Description and recommendationsCross sanding minimizes the fibre to rise. Cross sanding facilitates remove veneer tape, glue and filler. Reduced sanding costs since the cross belt prolongs the life time of the wide belts. Cross sanding gives a plain surface to the softer and harder parts of the working piece.4. Sanding methods 4.2. Cross sanding4.2.2. Stock removal recommendations4. Sanding methods 4.3. Surface sanding4.3.1. Description and recommendationsThe required surface must be achieved without large stock removal.The conveyor belt should have a hardness of approx. 40-50 durometers. 4. Sanding methods 4.3. Surface sanding 4.3.2. Stock removal recommendations
4. Sanding methods 4.4. Lacquer sanding4.4.1. Description and recommendationsNormally a product with grains of silicon carbide is used. Use as low sanding pressure as possible to reduce friction. The lacquer must be well cured. When sanding hard lacquers a product with grains of aluminium oxide is recommended.4. Sanding methods 4.4. Lacquer sanding4.4.2. Recommendations4. Sanding methods 4.4. Grit combinationRaw material ManufacturingConvertingSurface sandingSanding faults: causes and actionsProduct recommendations5. Sanding faults: causes and actions5.1. Chatter marksDescription
Transverse sanding faults on the work piece5. Sanding faults: causes and actions5.1.a. Chatter marks5. Sanding faults: causes and actions5.1.b. Chatter marks5. Sanding faults: causes and actions5.2. Blank linesDescription
Longitudinal, oscillating blank lines, no ridges
5. Sanding faults: causes and actions 5.2.a. Blank lines5. Sanding faults: causes and actions 5.3. Blank linesDescription
Longitudinal, oscillating short narrowblank lines, no ridges
5. Sanding faults: causes and actions 5.3.a. Blank lines5. Sanding faults: causes and actions 5.4. Unbroken ridges
DescriptionLongitudinal, unbroken and narrow oscillating ridges
5. Sanding faults: causes and actions 5.4.a. Unbroken ridges5. Sanding faults: causes and actions 5.5. Broken ridges
Description
Longitudinal, short and narrow oscillating ridges. Sometimes only following the oscillation in one direction. See the picture
5. Sanding faults: causes and actions 5.5.a. Broken ridges
Causes1. Too big removal because of to high sanding pressure2. Too low belt speed3. Too hard pad 4. Too wide pad5. Poor dust extraction or poor function of the air jet blower. Sometimes both
Actions1. Decrease the sanding pressure2. Increase the belt speed3. Change to more soft pad4. Try with a pad there the width is 80-90mm5. Check the dust extraction and the air jet blower
5. Sanding faults: causes and actions 5.6. Straight short ridges
Description
Longitudinal, 10 – 50mm long and straight ridges.Mostly appear when you are sanding lacquer5. Sanding faults: causes and actions 5.6.a. Straight short ridges
Causes1. Too big removal because of to high sanding pressure
2. Too low belt speed3. Too low conveyor speed4. Poor dust extraction or poor function of the air jet blower. Sometimes both Actions1. Decrease the sanding pressure2. Increase the belt speed3. Increase the conveyor speed4. Check the dust extraction and the air jet blower. Not: With good dust extraction and good cleaning of the belt, generally this type of problem do not appear5. Sanding faults: Causes and actions 5.7. Straight ridgesDescriptionLongitudinal, straight ridges. Not oscillating.This type of sanding fault is created by the sanding machine
5. Sanding faults: Causes and actions 5.7.a. Straight ridgesCauses1. The contact roller is damaged2. The graphite is damaged
Actions1. Resand the roller. 2. By lighter damage: sand the graphite with an abrasive P120. Is the graphite heavily damage change it.5. Sanding faults: causes and actions 5.8. ScratchesDescription
Longitudinal, short oscillating scratches
5. Sanding faults: causes and actions 5.8.a. ScratchesCauses1. Coarse grains in the sanding belt 2. Impurities in the joints or on the surface of the belt3. Break marks in the sanding belt
Actions1. Change the sanding belt2. Check the joint and the surface of the belt Change the sanding belt if necessary 3. Change the sanding belt
5. Sanding faults: Causes and actions 5.9. ScratchesDescriptionLongitudinal, straight scratches. Not oscillatingThis type of sanding fault is created by the sanding machine
5. Sanding faults: Causes and actions 5.9.a. Scratches
Causes1. Foreign particles on pressure beams or pressure rollers2. Foreign particles on the graphite 3. Foreign particles between the felt and the graphite
Actions1. Clean the pressure beams and the pressure rollers2. Sand the graphite with an abrasive, P120 2. Clean the felt
5. Sanding faults: Causes and actions5.10. Burning marks Description
Longitudinal, burning marks5. Sanding faults: Causes and actions5.10.a. Burning marks Causes
1. Heavy clogging of the sanding belt2. Not enough cutting power in the sanding belt, because of to high sanding pressure/ too much removal, (the grains has lost there sharpness)
3. Not enough cutting power in the sanding belt, because of to fine grit4. Foreign particles between the graphite and the felt. (sanding pad) 5. Raising damage in the contact rollerActions1. Change the sanding belt2. Change the sanding belt3. Change to a coarser grit4. Take out the pad unit and clean it5. Repair the damage
5. Sanding faults: Causes and actions 5.11. Sanding throughDescription
The veneer is sanded through in the middle of the work piece
5. Sanding faults: Causes and actions 5.11.a. Sanding through5. Sanding faults: Causes and actions 5.12. Sanding throughDescription
The veneer is sanded through in one side of the work piece
5. Sanding faults: Causes and actions 5.12.a. Sanding through5. Sanding faults: Causes and actions 5.13. Sanding through Description
The veneer is sanded through on the left side or on right side of the work piece, or on the both sides
5. Sanding faults: Causes and actions5.13.a. Sanding through5. Sanding faults: Causes and actions5.14. Sanding through Description
The veneer is sanded through on the front edge
5. Sanding faults: Causes and actions5.14.a. Sanding through5. Sanding faults: Causes and actions5.15. Sanding through Description
The veneer is sanded through on the back edge
5. Sanding faults: Causes and actions5.15.a. Sanding through5. Sanding faults: Causes and actions5.16. Sanding throughDescription
The veneer is sanded through on the inner edges of the frame detail
5. Sanding faults: Causes and actions5.16.a. Sanding through5. Sanding faults: Causes and actions5.17. Wavy surface (solid wood)Description
The surface of the solid wood is uneven, (wavy)This problem appear especially on soft wood
5. Sanding faults: Causes and actions5.17.a. Wavy surface (solid wood)5. Sanding faults: Causes and actions 5.18. Sanding through ( lacquer ) Description
The surface of stain and lacquer is sanded through on some parts of the work pieces
5. Sanding faults: Causes and actions 5.18.a. Sanding through ( lacquer )5. Sanding faults: Causes and actions 5.19. Sanding through ( lacquer )
DescriptionThe surface of lacquer is sanded through on the left side or on the right side of the work piece, or on the both sides
5. Sanding faults: Causes and actions 5.19.a. Sanding through ( lacquer )5. Sanding faults: Causes and actions 5.20. Sanding through ( lacquer ) Description
The surface of lacquer is sanded through on the front edge or on the back edge of the work piece, or on the both edges
5. Sanding faults: Causes and actions 5.20.a. Sanding through ( lacquer )5. Sanding faults: causes and actions 5.21. Ridges
Description
Longitudinal, 15 – 80mm long and straight ridges.
5. Sanding faults: causes and actions 5.21.a. Ridges
Causes1. Too big removal because of to high sanding pressure2. Too low belt speed3. Lacquer not sufficiently dry4. Poor function of the air jet blower5. Poor dust extraction6. Too low conveyor speed
Actions1. Decrease the sanding pressure2. Increase the belt speed3. Check the drying system4. Check the air jet blower4.a Install a 2nd air jet blower for better cleaning of the sanding belt 5. Check the dust extraction6. Increase the conveyor speed
Not: With good dust extraction and strong air jet blower for cleaning of the belt, generally this type of problem do not appear
5. Sanding faults: causes and actions 5.22. The surface is not sufficiently sanded
Description
The surface of lacquer is not sanded even all over the area
5. Sanding faults: causes and actions 5.22.a The surface is not sufficiently sanded
Causes1. Too low sanding pressure2. Too low belt speed3. Too fine grit used4. The sanding pad is too hard and not flexible enough 5. The graphite is worn out
Actions1. Increase the sanding pressure2. Increase the belt speed3. Try a coarser grit 4. Use a softer felt or use a mix of felt and foam-rubber5. Change the graphite 5. Sanding faults: Causes and actions5.23. Folding of the belt
Description
The wide belt usually folding in the middle of the belt
5. Sanding faults: Causes and actions5.23.a Folding of the belt
Causes1. Too high belt tension. Is usually the primary cause 2. Too high sanding pressure3. Incorrect oscillation, too fast in one direction or in both directions4. The belt is not dry5. Unequal belt tension, (when the machine has two cylinders on each unit for the belt tension)
Actions1. Decrease the sanding pressure to maximum 4 bar. It is usually enough for all type of wide belt machines2. Decrease the sanding pressure3. Store the belt in a dry place4. Adjust the pressure to equal in both cylinders5. Sanding faults: Causes and actions5.24. Belt breakage
Description
Belt breakage in the material or joint
5. Sanding faults: Causes and actions5.24.a. Belt breakage
Causes1. The photocell for the oscillation is not working 2. The photocell is too strong3. A damage at the edge on the belt has occurred when the belt was changed4. Improper storage of the sanding belt. They have been conical and run out of the machine5. The joint is not strong enough, because of a fault in the production
Actions1. Clean the photocell from dust or change it if not working2. Adjust the photocell. If it is no possibility to adjust the intensity, cover the photocell with one layer of brown tape3. Cut away the damage of the edge if it is not more then 10 mm deep. Cut out as half-moon4. Store the belts in a dry place on wood or board, or hanging on rack5. Inform the supplier
5. Sanding faults: Causes and actions5.25. Belt flapping
Description
The belt edge is flapping
5. Sanding faults: Causes and actions5.25.a. Belt flapping
Causes1. Improper storage of the sanding belts2. High air humidity variations3. Improperly made joint
Actions1. Store the belts in a dry place on wood panel or board, or hanging on rack2. Control the variations of the air humidity in store room and sanding area
3. Inform the supplier5. Sanding faults: Causes and actions5.26. CuppingDescription
The sanding belts have a tendency of cupping
5. Sanding faults: Causes and actions5.26.a. Cupping5. Sanding faults: Causes and actions5.27. Irregular belt oscillationDescription The sanding belt is hard to steer
CausesFault within the air cylinder or the photo cell/sensorImproper storage of the sanding belt. They has been conical Improperly made jointToo low belt tension
5. Sanding faults: Causes and actions5.28. Bad stock removalDescription The stock removal is too low
CausesToo low sanding pressure Too high conveyor speed Too fine grits are used The contact roller is too softThe sanding belts are clogged
5. Sanding faults: Causes and actions5.29. Uneven sanded surfacesDescription The sanding gives an uneven surface
CausesTechnical error in the pad or a fault in the controlling unitDust in the contact elementsUnequal thickness of the working pieceWrong choice of grits and grit combinationUneven conveyor speed
5. Sanding faults: Causes and actions5.30. Short life time Description The life time of the belt is short
CausesToo high sanding pressure / too high stock removalBad dust extraction systemBad air jet blower for the belt cleaningWrong grit combination
5. Sanding faults: Causes and actions5.31. Dusty machineDescription The machine gets dusty
CausesThe dust extraction does not work properlyThe dust extraction is undersized High electrical charges
5. Sanding faults: Causes and actions5.32. Poor lacquer adhesionDescription Poor lacquer adhesion
CausesToo fine surfaceToo fine grits are used
5. Sanding faults: Causes and actions5.33. High consumption of stain or lacquerDescription Too high consumption of stain or lacquer
CausesThe surface is too coarseToo low sanding pressure Wrong grit are used.Use finer gritWrong grit combination
Construction and raw material ManufacturingConvertingSurface sandingSanding faults: causes and actionsProduct recommendations
6. Product recommendations6.1. Wide belt sanding, incl.cross belt.Sanded products Sanded material Ekamant produktDoors Solid wood or veneer PKFO, ARKFO Table tops Hard wood RKXH Parquet Solid wood or veneer PKFO, ARKFO Soft wood ARKFEO, ARSFEO RKXH
Plywood Veneer PKFO, ARKFO Ship board / MDF and Plastic, board, ARSF, ARSFEO laminated panels Corian All the above Lacquer AESM Filler AESMNS Ground coat
6. Product recommendations 6.2. Long narrow belt sanding (stroke sanders) Sanded products Sanded material Ekamant product
Table tops Solid wood or veneer PKFO, ARKFO Hard wood RKXH, RKJ
Solid wood or veneer PKFO, ARKFO Soft wood ARKFEO RKXH, RKJ
Ceiling panels Solid wood or veneer PKFO, ARKFO Hard wood
Solid wood or veneer PKFO, ARKFO Soft wood ARKFEO RKXH, RKJ
All the above Lacquer AESM Filler AESMNS Ground coat
6. Product recommendations 6.3. Edge sandingSanded products Sanded material Ekamant product Furniture details Hard wood PKFO, ARKFO RKXH
Soft wood PKFO, ARKFO, ARKFEO RKXH
Stairs Solid wood or veneer PKFO, ARKFO, ARSFEO RKXH 6. Product recommendations 6.4. Profile sandingSanded products Sanded material Ekamant product
Legs Turned details RKJ, RKJFO of solid wood
Furniture details Solid wood or veneer RKJ Big radius
Solid wood or veneer Small radius RKJFO
Moulding details Solid wood RKJFO
All the above Lacquer RKJFON Filler Ground coat