Particle Board QC Inspection Checklist : Part 2 particleboard manufacturing defects and causes
Purpose of the work
The present work aims to show how application of statistical methods can help identify sources of losses in the form of faulty products, analyze their causes at wood chipboards production.
Laminators of particleboard require a smooth, even surface, especially when applying thin papers or foils to the substrate. Undetected defects in the substrate surface can lead to poorly laminated finishes.
Some main causes of these surface defects arise from improper sanding techniques. Even though many of these sanding defects are hard to detect to the untrained eye, they usually won’t be seen in the field because of quality control at the manufacturing plant.
The pictures and descriptions in this guide can be helpful in spotting particleboard surface defects, There’s nothing better than chalking or examining the board by touch to detect defects.
PHOTO : Streaks Description: Uneven sanding. Usually a variation in panel smoothness or sheen, not thickness Probable cause: Loaded or worn sanding belts Troubleshooting: Replace sanding belt or smoothing bar
PHOTO : Sand Through Description: Removal of fine surface material, causing the large material of the core layer to show through Probable cause: Panel is too thick when it enters the sander, or an unequal amount is sanded off one side Troubleshooting: Adjust sanding press
PHOTO : Scratch Description: The panel appears to have scratch marks down its length Probable cause: Inconsistent abrasive grain dispersion on sander belts or finishing heads not working properly Troubleshooting: Replace sanding belts or adjust finishing heads
PHOTO : Hesitation Description: Dip in surface caused by idling sanding head when a panel stops or hesitates in the sander Probable cause: Feeder belt slippage, or an extra thick panel disrupts the feed rate Troubleshooting: Reject the board
PHOTO : Thin Description: Yellowish areas on the panel surface Probable cause: The pre-cured layer has not been sanded off because the panel is too think for the sander. Troubleshooting: Panel production problem; reject board
PHOTO : Chicken Scratch Description: Raised or gouged area on surface Probable cause: Decreased amount of abrasive concentration on sander belt Troubleshooting: Replace sanding belts
PHOTO : Ridges & Grooves Description: Thickness variations on panel surface. May appear in a straight line (smoothing bar related) or back and forth across the panel (sanding belt related) Probable cause: Caused by poor sanding belts or smoothing bar Troubleshooting: Replace smoothing bar or sanding belts
PHOTO : Snipe & Rollover Description: Snipe: tapering off at about an inch from the end of the panel Rollover: tapering along length of panel Probable cause: Improper panel feeding into the sander, or too much pressure is applied along the panel edges Troubleshooting: Snipe: Butt panels together and keep straight when feeding Rollover: Adjust smoothing bar pressure by angle-cutting or tapering the felt on the ends
PHOTO : Chatter Description: Pattern of marks appearing across the board, usually appearing within 12 inches of the edge of the panel Probable cause: In most situations, the problem is caused by not enough pressure on the smoothing bar. Out-of-balance rolls and bearings or an abnormally thick belt splice may also cause chatter Troubleshooting: readjust pressure on smoothing bar
KEYWORDS : defect, faulty products, statistical methods of control, wood chipboards,
most frequent defects: sanding defects, pulling off/ blisters, dust and tar pitch, short and flocculent boards.
Choice of technical measures allows increasing effectiveness of functioning of wood chipboards production, which is connected with launch of quality and competitive products for broad utility in building, special purpose furniture production, and constructions working in atmospheric conditions . The main purpose of commercial organization is to get a profit , provided that one of effective ways of increasing profit is decreasing expenses. Furthermore, expenses need to be identified, evaluated and controlled. Nowadays not all expenses can be decreased, for instance, it is not recommended to decrease expenses on quality materials and salary. However, some part of expenses, which is called losses , can and must be decreased for increasing effectiveness of activity, competitiveness, and profitability of an enterprise. Losses are expenses for mismatches; classification of expenses for quality was fully presented in . It is possible to decrease expenses for mismatches by identification of faulty products, analysis of causes of faulty products and exclusion or minimizing their influence. Most enterprises keep a record of characteristics of quality of production in the form of a report of different types of faulty products. This allows evaluating losses from faulty products in monetary equivalent without additional studies. Statistical methods of quality control of production and processes can be effective methods of managing losses.