CNC Workholding and Fixturing

Question 1

What is the primary purpose of a CNC vise stop (work stop)?

Accepted Answer

To provide a repeatable datum for part positioning

Answer

To prevent the vise from moving during cutting

Answer

To increase clamping force on the workpiece

Answer

To align the vise parallel to the X-axis

Question 2

When using a machine vise, why should the workpiece be tapped down with a mallet after initial tightening?

Accepted Answer

To seat the part firmly against the parallels and prevent lifting

Answer

To work-harden the contact surfaces

Answer

To test the vise jaw clamping force

Answer

To check for proper coolant flow

Question 3

What type of workholding device uses a magnetic field to hold ferrous workpieces without mechanical clamping?

Accepted Answer

Magnetic chuck

Answer

Vacuum chuck

Answer

Collet fixture

Answer

Step clamp set

Question 4

In modular fixturing, what is the primary benefit compared to dedicated fixtures?

Accepted Answer

Reconfigurability for multiple part families without building new fixtures

Answer

Lower upfront material cost per fixture

Answer

Faster machining cycle times

Answer

Better accuracy than welded fixtures

Question 5

What is the 3-2-1 locating principle used for in CNC workholding?

Accepted Answer

Constraining all six degrees of freedom with the minimum number of contact points

Answer

Defining three axes, two planes, and one origin point

Answer

Setting three clamp positions for balanced force

Answer

Aligning a part using three dial indicator readings

Question 6

Why should parallels used in a vise be matched pairs of the same height?

Accepted Answer

To keep the workpiece level and prevent rocking during machining

Answer

To ensure equal clamping force on both sides

Answer

To allow proper coolant drainage beneath the part

Answer

To match the vise jaw height for correct tool reach