Saw guide pressure feed speed control systems and methods

A method for making a bandmill cut through a workpiece, said bandmill having a sawblade, the sawblade having a cutting edge, a trailing edge, and first and second side faces connecting the cutting and trailing edges, a top sawguide and a bottom sawguide, each sawguide having a FRONT face enabled to contact and pre-strain the sawguide against the first side face of the sawblade for making a cut through a workpiece, a motion controller and a motion drive mechanism for controlling workpiece feedspeed;

• wherein said method is characterized by:
• (a) providing an anti-deviation feedback loop controller to an operator of a bandmill, said anti-deviation feedback loop controller comprising:
• i) a force sensor operatively coupled to a second face of said bottom sawguide, wherein said force sensor is enabled to sense a dynamic sawblade deflecting force of a side of the sawblade against the FRONT face of the bottom sawguide in real time while sawing a workpiece, said sawblade deflecting force caused by saw feed velocity through a nonuniform workpiece and preceding a lateral deflection of said sawblade toward or away from said FRONT face of said bottom sawguide during a cut, said force sensor to generate an electrical signal of a magnitude and a direction of said sawblade deflecting force;
• ii) an anti-deviation control system configured to receive said electrical signal from said force sensor, and to determine a feedspeed adjustment output therefrom;
• iii) a motion drive mechanism enabled to receive said feedspeed adjustment output from said anti-deviation control system and drive a workpiece feedspeed in response thereto;
• (b) pre-stressing said sawguide by laterally displacing said bottom sawguide against said first side face of the sawblade;
• (c) configuring said anti-deviation control system to digitally zero said electrical signal between cuts, such that a positive value of said electrical signal during a cut is associated with a lateral deflecting force of said blade in a first direction and a negative value is associated with a lateral deflecting force of said blade in an opposite direction;
• (d) operating said force sensor in
• i) a zero set state wherein said force sensor is elastically pre-strained in compression by statically pre-stressing said sawguide against said blade and digitally zeroing said electrical signal;
• and,
• ii) an anti-deviation detection state wherein force sensor is elastically compressed or relaxed during a cut by any lateral deflecting force of said blade against or away from said sawguide and said electrical signal may range around zero from a positive value to a negative value, and,
• (e) while cutting a workpiece, monitoring said magnitude and direction of said sawblade deflecting force and operating said motion drive mechanism under control of said anti-deviation control system so as to forestall any lateral deflection of said first side face of the sawblade perpendicular to the first side face of the sawblade from a true cut line, thereby operating an anti-deviation feedback control loop.