Linear Direction Change Without a Radius
When an internal corner is programmed as a straight linear motion (G01) with a 90-degree turn into another straight linear motion, there are few things that happen that may lead to gouging.
- The radius of the tool forms the radius in the part.
- The engagement on the tool greatly increases, this causes excessive tool deflection.
- The tool will come to a complete stop, extra material will be cut at this small dwell leaving a gouge or witness mark.
Add a fillet radius (G02/G03) to the corner that is larger than the tool's radius.This lets the machine cut the corner more gradually and prevents the motion that can cause gouges.
Setting 191 (Default Smoothness) Has an Incorrect Value
This setting defines the smoothness setting between Rough, Medium, or Finish. Each of these options represents a set of values for feed acceleration and deceleration.
The Rough option uses the least restrictive values to decelerate faster into corners, change direction more quickly, and accelerate faster out of corners to reduce cycle time, at the expense of part finish and machine accuracy. Use this option to rough out a part, or to decrease cycle times when part finish and accuracy are not critical.
The Medium option uses the machine’s default values.
The Finish option uses the most restrictive values to decelerate more slowly into corners, change directions more slowly, and accelerate more slowly out of corners to improve finish, at the expense of a longer cycle. Use this option for finish cuts on complicated shapes or when part finish and accuracy are critical.
Setting 85 (Maximum Corner Rounding) Has an Incorrect Value - Mill
Setting 85 defines the machining accuracy tolerance around corners. The default value is 0.025" (0.635 mm). If the value of Setting 85 is too low, the control may interpret exact stops between lines of code. This can cause jerky motion, finish problems, and repeatability problems.
The control can cut corner  within tolerance at a higher feedrate than it can cut corner .
Use this setting to smooth out the motion of the machine in corners, or to make the machine more accurate when trying to hold a close tolerance.
A higher value for this setting lets the machine maintain higher feedrates through a corner for decreased cycle times, but it allows more deviation from the programmed path. A lower value reduces deviation, but also reduces the feedrate for increased cycle times.
Note: Setting 191 affects Setting 85. For example, when Setting 191 is ROUGH, the value of Setting 85 is multiplied by 4. When setting 191 is FINISH, the value of Setting 85 is divided by 4.
You can use G187 to temporarily override Setting 85 in a program. The E address with G187 commands the temporary corner rounding value. For example, G187 E0.005 temporarily sets the corner rounding value to 0.005. Refer to your Operator’s Manual for more information about G187, Setting 191 and Setting 85.
The Machine is Not Level - Mill
To operate correctly, the machine must be level. An out-of-level machine can have problems such as poor surface finish, accuracy and repeatability issues, out-of-round circular motion, and out-of-true linear motion.
Watch the VMC Leveling video to learn how to properly level your Haas VMC, or contact your Haas Factory Outlet to have your machine’s level checked.
High-Speed Machining (HSM) not Activated
High Speed Machining (HSM) uses a unique "look ahead" function to anticipate machine motion.
In traditional machining, the axis motor must decelerate at the end of each programmed move. Without the ability to look ahead, the machine slows at a consistent rate throughout the program. HSM "looks ahead" through the next 80 lines of code, which lets the control anticipate upcoming movements and vary the deceleration rate. This lets the machine complete the program much more quickly. The control calculates the angle of intersection between the linear and/or the circular motion strokes to maintain the maximum possible velocity through the stroke transition.
The machine can move through wide-angle direction changes more quickly. The greater the change in direction, the slower the machine must go to make the corner, down to a minimum velocity of zero for a direction change of 90 degrees or greater.
- Without HSM, the machine decelerates at the same rate at every change in direction, regardless of the width of the angle.
- With HSM's unique ability to look ahead in the program, the deceleration is variable. Thus, the part is completed faster.