What is the cause of jumping knife of spindle veneer rotary cutting machine?
After adjusting the knife height in proportion, when adjusting the knife gap, observe the wood core to identify which side is not smooth. Adjust the knife gap according to the side where the wood core is not smooth. When adjusting the knife gap, there is no need for measurement; simply observe the wood core and the veneer sheet. Make adjustments gradually, and avoid making drastic changes at once.
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Veneer rotary cutting machine is one of the main equipment in the production of plywood. They can be classified into chucking and spindleless rotary cutting machines. With advancements in technology, people have applied digital servo control technology in rotary cutting machine production. In recent years, CNC (Computer Numerical Control) spindle veneer peeler machines have emerged. The introduction of CNC rotary cutting machines has not only improved the quality and precision of veneer production but also significantly increased production efficiency and the level of automation in the machine.
Please note that the translation provided above is a direct translation of the text. It is always important to consult with experts, follow the manufacturer’s guidelines, and adhere to industry best practices when operating and adjusting face veneer rotary cutting machines to ensure safety and optimal results.
Common faults and adjustment methods for spindleless veneer peeling machines:
Uncompact veneer surface
Cause: Unevenness in knife straightness, excessive roller runout, excessive pressure, severe difference between the sapwood and heartwood of the wood, and thin and curved wood.
Correction method: Re-sharpen the cutting tools and check the straightness of the blade. If there is roller runout, inspect whether the bearings are damaged or if there is excessive radial clearance. Check if the roller heads have deformed due to excessive pressure from curved or flattened wood, which can affect the smoothness of the veneer. In case of runout, replace the roller or perform necessary corrections. Excessive pressure from single or double rollers and the blade due to low blade height or small blade gap can also cause irregular deformation of the wood, affecting the evenness of the veneer. Please refer to the specific measurement methods for blade position carefully.
In the case of thin and curved wood, during the peeling process, the wood is forcefully straightened and peeled due to the powerful automatic feeding pressure of the machine. After being peeled, the wood tends to shrink and bend according to its original curvature, resulting in unevenness. As wood grows or is stored for a long time, it tends to have one side facing the sun and the other side facing the shade. As a result, there are differences in density and moisture content between the two sides, leading to variations in the evenness of the peeled veneer. Therefore, careful wood selection is also crucial.
Proper maintenance, regular inspections, and adherence to manufacturer guidelines are essential for the smooth operation and optimal performance of spindleless veneer peeling machines.
Uneven veneer surface:
Cause: Incorrect blade position, dull blade, excessively small or large blade gap. Wood is too dry or hard, carbon brush of the electromagnetic clutch is loose, improper adjustment of the gap between the pressure bars on both sides of the knife table.
Correction method: Re-sharpen the blade to make it sharp and use an oilstone to polish it. When the blade position is too high and the blade gap is too large, the wood tends to jump when the remaining peeling is small, resulting in a curtain-shaped surface and a square or hexagonal wood core. When the blade position is too low or the blade gap is too small, the wood undergoes several times the normal peeling pressure, causing excessive deformation and unevenness in the peeled veneer.
Sometimes, the machine may experience intermittent feeding during peeling. In such cases, simply rotate the carbon brush downward by one or two turns. If the oil box is running low on oil, refill it with clean thin machine oil to prevent clutch burning or slipping. Excessive shaking of the knife table during peeling can also lead to unevenness on the veneer surface. To adjust, check and tighten all fastening screws, and adjust the distance between the pressure bars on both sides and the slide blocks of the knife table to 0.2-0.5mm. Remember not to adjust it too tightly.
Uneven thickness and fan-shaped veneer due to inconsistent thickness of remaining wood core at both ends:
Cause: Inconsistent blade height at both ends, inconsistent blade gap at both ends, damaged single roller bearing, loose or missing screws, sliding block and bottom bar of the knife table, loose screws on the slide track, inconsistent feed screw.
Correction method: Inconsistent blade height at both ends will result in uneven thickness of the veneer on both sides, leading to diagonal veneer and a wood core that is larger at one end and smaller at the other. The side with higher blade height will have a thinner wood core, while the side with lower blade height will have a thicker wood core.
Inconsistent blade gap at both ends has a similar impact as inconsistent blade height. The side with a smaller blade gap will have thinner veneer and a thicker wood core, while the side with a larger blade gap will have thicker veneer and a thinner wood core. Simply adjusting the blade height and blade gap to be consistent will restore normal operation.
When a single roller bearing is damaged, the deformed bearing will cause an excessive blade gap at the damaged area, resulting in a thinner wood core.
Loose or missing screws on the sliding block, slide track, or other parts of the knife table can directly affect the balance, stability, and uniformity of the feed, leading to inconsistent thickness of the wood core. It is important to regularly check for loose or missing screws and promptly replace any damaged or easily damaged parts to prevent potential issues and avoid unnecessary downtime and losses.
If there is inconsistency in the feed, worn-out feed nuts, or loosened screws on the transmission shaft seat, people adjust the corresponding number of teeth to advance or retreat the lead screw (each pitch is 0.8mm).
