User guide

Appendix l D-3
Blade and Bushing Lubrication
Common cutting lubricants
Commonly used general purpose lubricants include:
• Tap water
• Dish washing liquid (Joy, etc)
• Glycol (anti-freeze, coolant)
• Water-soluble silicone cutting oils
• Diesel fuel
• Mold release
• Mineral oil
Medical grade lubricants:
• Distilled water
• Isopropanol (isopropyl alcohol)
• Mixtures of isopropanol and water
Lubrication systems
The most basic blade lubrication system for rotary knife cutters is using a stainless
steel tray filled with the lubricant. Because the cutting blade passes through the
tray during every cutting cycle, the blade is lubricated before each cut. This
approach limits material buildup on blade and bushing surfaces for most applica-
tions. Care must be taken to maintain the lubricant level within the tray. Clean out
accumulated cut residue on a regular basis.
Spray mist systems can be used to lubricate either the blade or the extrudate as it
enters the cutter bushings. These systems allow the application of a minimum
amount of lubricant with good consistency. If the mist is applied to the product as
it enters the cutter bushings, the lubricant will minimize the drag between the
bushing bore and the tube or profile, as well as wet the blade and bushing faces.
With flexible and/or sticky materials this can improve both cut quality and cut-to-
length accuracy.
The last method of blade lubrication (and the oldest) is the blade wipe system.
Felt, sponge, or some other absorbent material is mounted so the rotary knife blade
will pass through it, with interference, before making a cut. Typically a gravity drip
or wick system is used to keep the absorbent material wet with lubricant. These
systems not only lubricate the blade, but also wipe off residue before each cut.
However, the operator must constantly observe the condition of the pads as they
wear quickly and lose their function. Another concern (especially in medical appli-
cations) is what happens to wear particles from the pads. This material frequently
ends up on the blade itself, and is then transferred to the very product it is meant to
protect from contamination.be especially noticeable on the top inside of the tube or
profile.
(continued)