Gentlemen, Drill wander is the byproduct of one of the following factors: 1. If you are using an extremely "hard" entry material, ie. phenolic or melamine, the drill can have a tendency to "skate" on the entry prior to penetration. This will usually cause excessive drill wander and have detrimental effects on front to back registration for obvious reasons. If you are using on of these types of entries, try using LCOA EO+ ( an aluminum clad cellulose core material) or 7 to 8 mil virgin aluminum foil. The EO+ seems to work better in suppressing drill wander. 2. If the flute to diameter ratio is too great ( greater than 20:1) than this can be a contributor to drill wander. The first thing that you should do is call your drill vender and have them analyze your situation. Many times they can offer a tool that better fits you particular application. If they don have any standard product for you to test, see if they will design a tool that better fits your needs. If your drill vender cannot build a special...get a new drill vender!!! 3. If the spindle runout is excessive, it can have an effect on drill wander. Contact your drill machine supplier and find out what their specifications are for spindle runout ( most are between .0002" to .0005"). Try to perform a runout check at least once per week. A fairly good barometer, should any spindle have excessive runout, is drill breakage, however, depending on the diameter of the tool you are using, this is not always the case. 4. Lastly, tool geometry and carbide selection can have an effect on drill wander. Designing cutting tools is a constant game of trade-offs. If you want a stronger tool that will have better resistance to breakage and deflection, the trade- off is usually a decline in hole quality. if you want a tool that will produce excellent hole quality, you can bet that you will have more breakage, increased drill wander, and reduced stack heights. The task of the drill room process engineer is to find the happy medium that will share the best of both worlds, however, it behooves the engineer to involve their machine and tool suppliers to assist in this endeavor. I wish you success in this project. Regards, Mark R. Ford, North East Application Engineer - Megatool *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To subscribe/unsubscribe send a message <to: [log in to unmask]> * * with <subject: subscribe/unsubscribe> and no text in the body. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * ***************************************************************************