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MACHINE CALIBRATIONS / LASER COMPENSATIONS
We provide a comprehensive machine geometry evaluation service by performing full machine error measurements, alignments, calibrations, characterizations, laser compensations, and analyses.  Our approach to machine accuracy correction is to identify the root cause errors, recommend and make adjustments for geometry errors where possible, and use compensation to address residual errors.  We perform full machine measurement (characterizations) and anything in between from machine rail to machine spindle to volumetrics.
 
We use the proper tools that to perform the job correctly and efficiently.  We take pride in having expertise in performing measurement, alignments, and analyses with Renishaw and Automated Precision Inc products, from single axis interferometry to laser trackers. 

 

We combine laser measurements from the API Radian Pro laser tracker and the API XD6 laser.  This enables us to see the whole picture.

  • The API Radian Pro Laser tracker allows us to compare geometric relationships like parallelism, squareness, and physical X,Y,Z coordinates of the machine to other critical machine features.  Furthermore, it allows us to check the accuracy of the machine anywhere in the work volume without limitations...it is our most versatile tool

The API XD6 Laser brings exceptional accuracy measurement performance and remains our standard for accuracy calibration.  It also measures Pitch, Roll, Yaw, and Straightness which provides us a complete understanding of the machine axis when performing alignments and compensation. 


















 

MACHINE ALIGNMENTS

An accurate machine begins with a good machine alignment.  This is a process that starts from the ground and ends at the tool tip, and there are no short cuts.  During this alignment process, we make sure the base axis or axes are co-planar, level, and straight.  It is imperative that this structure maintains these characteristics when the rest of the machine traverses across it, so sufficient and equal pre-load must be applied at each leveler or foot pad.  This can be a cumbersome feat, especially when the foundation may be in question or the foundation design incorporates isolation foam beneath and around the machine. 

 

If geometry is not within original specifications, the best approach towards restoring the machine to original performance, is to perform a machine alignment.  This will straighten the aligned machine axis, minimize the angular errors Roll, Pitch, Yaw, and ensure they are square to the other axes.  Oftentimes, after an alignment, the machine accuracy comes within specification without having to perform compensation, especially when the last time the machine as last compensated was during initial machine installation.  This means the alignment performed is representative of the initial installation and that the changes in accuracy were attributed to the changes in the machine geometry.  

 

We have the experience and the tools to achieve the best alignment results, regardless of the machine and foundation design.  We are experts and pride ourselves in tackling these complex issues.

ACCURACY COMPENSATION
CNC machines all require some form of travel or distance calibration; even if equipped with an external linear or rotary feedback mechanism that is attached to the moving element.  The original calibration is usually done by the factory or OEM prior to machine delivery and then once again at machine installation; especially if it is a large machine tool.  The machine will eventually change for 3 main reasons, ultimately affecting the accuracy performance of the machine. 

The reasons for machine tool accuracy performance changes are listed in the order of likely occurrence:
                                           1.  Wear and looseness in the axis drive mechanism
                                           2.  Geometry shift due to changes in weight load distribution occurring at the machine base jacks
                                           3.  Unplanned catastrophic events (machine crash)
                                           4.  Large temperature fluctuations occurring daily or seasonally
                                           5.  Foundation shifts due to natural phenomena or settling of new foundation

Even if fitted with a linear feedback device like a Heidenhain scale, the accuracy performance of the particular axis is only as good as the angular errors (Roll, Pitch, Yaw) and straightness performance of the axis..., and the accuracy of the axis will be increasingly worse farthest away from the feedback mechanism due to abbe error.  This explanation of accuracy within the volume is a portion of the volumetric accuracy of the machine.  Our equipment allows us to calibrate the machine axis where the machine at the positions where it is being used the most, in order to have maximum impact on the parts being machined.  We have the versatility to produce the proper corrections where it is needed.

thomas@tomcat-machine.com                                                  Phone:  860-837-3172                                                                                   USA

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