Troubleshooting Tips: Centerless Grinding Concave work (low center)`, Work guides on entrance and exit sides deflected toward the grinding wheel. Also see . Centerless grinders are the dependable workhorses of the manufacturing world. With regular maintenance and TLC, your centerless grinding. Achieving consistent and quality results from the centerless grinding process requires an understanding of the basic fundamentals. Most application problems .
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Below, are listed problems, which may be encountered whilst grinding. Under each are listed probable causes, and under each cause, possible corrections.
Possible corrections are used advisedly here. It is practically impossible to establish hard and fast rules for turning out perfect grinding. There are many variables, which must be correctly attuned, gginding variables, which must be correctly attuned, and an apparently irrelevant one may prove to be cause of trouble experienced.
Also, the same cause may produce a varied number of grinding problems.
Grinding wheel too hard for particular work. Use a coarser grained wheel with more open bond to allow greater chip clearance. Scale from hardened work, or dirty oil, solder, welding flux, etc. Clean work before grinding.
Dress wheel more often. Incorrect dressing of grinding wheel Turn diamond or replace with new hrinding. Increase rate when dressing. Stock removal too fast.
Take lighter cuts or infeed at slower rate. Increase regulating wheel work speed to make wheel act softer. Coolant incorrect or dirty. If using soluble oil, use thinner coolant, add soda, or if necessary filter coolant. Incorrect wheel for center,ess job.
Scale from hardened work dulls wheel grains. Incorrect dressing of grinding wheel Turn diamond to avoid fiat spot or replace with new cwnterless. Increase penetration of dressing diamond up to 0. Check slides on truing attachment; they may be worn low in centre.
Truing attachment gibs may be loose enough to allow diamond to back off instead of cutting. Decrease concentration of soluble oil. Increase flow of coolant. Centefless coolant tank and machine. If water hard, treat with a water softener before mixing with oil. Increase soda or decrease oil content of coolant when using soluble oil.
Improper work support blades Change blade to a softer material; if tungsten carbide was used, try steel, cast iron or aluminium bronze. Wide irregular marks, varying in depth, from too soft a wheel Use harder grade wheel. Widely spaced spots on work piece due to oil or glazed spots on wheel True spots out of wheel, balance and redress. Avoid getting oil on wheel. Even venterless spiral diamond lines Dress at slower traverse rate. Diamond cracked or broken; replace.
Centreless Grinding Troubleshooting – Midland Abrasives
Diamond holder loose; tighten clamping screw. Try lighter diamond cuts. Make final dressing in opposite direction to initial runs.
Even spiral lines on work piece whose lead corresponds to feed rate. Dress troublehooting face parallel to work piece to prevent leading or trailing edge from digging in. Use crowned cam when dressing grinding wheel. Cut back front of face of wheel approximately half of stock removal over 1″ distance for a six-inch wheel relatively more on wider wheels Increase or decrease successive traverse rates to break pattern of diamond lines.
Troubleshooting Tips: Centerless Grinding
When through feed grinding, make certain guides on regulating wheel side are parallel and even with wheel face. Uneven fine lines on work piece due to faulty dressing Do not allow diamond to dwell on wheel. Barely contact wheel face at high spot—dress across face only, starting at an edge, do not start on face.
Maintain diamond traversing at an even rate.
Uneven, or evenly spaced lines on work piece due to extraneous vibrations If impossible to change machine location, mount grinder on some vibration insulating material. Be certain insulation is thick enough to be effective. If it is not sufficient, the natural frequency of grinder normally damped out by rigid construction may be emphasised and combine with external vibration to make conditions worse.
Wavy traverse lines due to faulty dressing, leaving ragged wheel edges. Round off wheel edges nicely—chamfering or dressing back is not sufficient. Try a different coolant, or if soluble oil used, cut down soda content of coolant. High soda concentrations attack resinoid and shellac bonds. Wheel too soft—use harder grade. Coarse grains or foreign matter in wheel face. Dress these out of wheel. Determine whether caused by type of wheel, dull diamond, dirty or too strong a coolant. Irregular scratches of various lengths and sizes due to dirty coolant.
Flush guards and wheel after each truing. Use coolant filter for fine finishes. Too great a difference in grain size between roughing and finishing wheels. Dress roughing wheel at slower traverse rate. Deep irregular marks caused by loose wheel. Use one standard paper washer blotting paper if other not available under flanges and tighten down.
Isolated deep marks due to improper dressing. Rotate or change diamond to—get sharper dressing. Wash wheel thoroughly with coolant after dressing. Reset gib on truing device. Grain marks due to too soft or coarse a wheel.
Substitute harder grade or finer grained wheel. Regulating wheel too hard. If regulating wheel too hard, work will spin and score on blade but it would be practically impossible to grind. Reset diamond or use new one. Use coarser or softer wheel.
Roughing wheel breaks down too fast. Rough grind with more and smaller cuts, or use harder wheel for roughing.
Grinding wheel out of balance. Inspect spindle and collet—remove cehterless if present. Use only one standard or blotting paper gasket under each flange. Make sure balancing stand is level both ways before attempting to balance wheel.
Always balance wheel in following sequence:. Motor bearing defective or armature out of balance. Renew motor bearings or balance armature.
Long blades will cause chatter unless blade angle is reduced. Also for small diameter work it will generally be necessary to reduce angle. Work support blade too thin Use a heavier blade. Blade length must be slightly longer than wheel width. Too heavy stock removal – particularly on in feed work.
Try lighter cuts and more passes. Wheel out of centerlesx. Make certain cap screws are troublesbooting in mount. Use only one gasket under each flange. When two are used constant soaking and drying out may eventually cause loosening of cap screws.
Radiac Abrasives | Centerless Grinding Archives – Radiac Abrasives
Type of wheel incorrect for particular job. Extraneous vibrations set up by nearby machinery. If impossible to change machine location, mount grinder troubleshootinv some vibration insulating material. If it is not sufficient, the natural. Loose spindle bearing Adjust spindle bearings.
If old type machine with plain bearings not Filmatic it may be necessary to rescrape bearings.