Maximizing the life of slitter tooling is a critical concern to everyone in the metal processing industry.  Lead times are often short and an unforeseen problem of chipped or broken tooling can be devastating to your company. Since careless handling and poor maintenance leads to machine downtime, discarded product and unforeseen delays; proper care and maintenance of tooling should be a key concern to all involved in the slitting process.  As a leader in the slitting tool industry we recognize this problem and offer these suggestions to maximize the life of your tooling between replacements.  

PROPER STORAGE

     Caring for your tooling starts in the storage area. A well-organized tooling storage area will help the operator make quicker and more efficient setups. Though metal processing is not necessarily a crisp, clean process, the storage area for tooling must be free of clutter and debris. Storing your knives should be done in an organized fashion and in an area that can include the correct supply of: 

•                       Shop rags

•                       Proper grit-stones

•                       Matching knife and spacer materials

•                       Cleaning fluid and tools for cleaning dirt grooves

•                       Area to lock up calibration tools

•                       Boxes to ship regrinds in

•                       Lubrication oil

•                       Other tools needed on the slitting line

Never store metal tooling in a horizontal position; this significantly increases the possibility of damage.  Tooling is placed on the shaft in a vertical position so storing the tooling this way is a good idea. We recommend knives be kept in a cabinet with individual vertical slots and remember to keep different knife sets and knives of different alloy make-ups separate. Spacers and bonded or metal stripper rings should be stored on an incline and with separate slotted vertical areas for master, or clearance, spacers. Rubber stripper rings may be stacked horizontally but should be separated as to male and female O.D. sizes. Plastic shims should be stored in their original packages and discarded after use.

SET UP

After determining the planned sequencing and correct clearances of the tooling, the arbor and each piece of tooling should be cleaned and inspected.  Knives must be checked for edge integrity and spacers for nicks or gouges prior to positioning them on the shaft.  Raised nicks may be carefully field-dressed, using the proper honing stone to match the surface finish of the tool.  After cautiously examining the knives, they should be placed on the arbor immediately. Once the arbor setup has begun, it should progress to completion and lock down. The arbor should never be left open due to the possibility of contamination or setup error.

When finished, the tools must be wiped clean and covered with a light application of oil to protect them from corrosion and returned to their respective slots. 

REGRINDING

 Knives must be reground regularly.  Frequent regrinding saves time and money because a dull knife leads to greater fatigue at the knife-edge because it is subjected to more force during the slitting process than a sharp knife.  Hairline cracks can occur if this fatigued material is not removed. Since all knives in the set must maintain the same outside diameter knives should be reground as a set.

The best indicator to when your knives need reground is the condition of the material's slitting edge. Marks on the slit coil usually indicate a chipped or out of round knife. Excessive burrs (when horizontal clearances are correctly assured) are another indication of a dull knife. An experienced operator is always the best determiner of a knife’s condition.

It is important to have proper storage and shipping containers whether the regrinding of the knives is done in-house or sent out.  Inadequate regrind boxes can lead to costly accidents. Each set of slitter knives should have an appropriately designed box that is lined, has individual knife slots, and a metal plate for additional reinforcement should surround it. It is important that the box can withstand the rough handling of shipment without damaging the sharpened knives. If rubber stripper rings are used, they should be ground as a set with the knives, maintaining their dimensional relationship of male and female usage.

The proper care and maintenance of your slitter tooling should be viewed as another way of increasing the efficiency of your production team.  If you would like more detailed information relating to your specific needs, please contact David Schwartz at 330/507-5586, or call our toll free number, 1-800-248-7421.