A provider of machine shop training offers these questions for benchmarking metalworking knowledge.
Editor-in-Chief, Modern Machine Shop
Expert Technical Training developed this test, which it gives to potential students to evaluate their need for the company's "Advanced CNC Milling and Drilling" course. A link to the answers can be found at the bottom of the questions.
1. What is the maximum rpm you should run a holder if it is unbalanced in a V-tapered spindle?
__ 4,000 rpm
__ 6,000 rpm
__ 8,000 rpm
__ 10,000 rpm
2. Unless it has a special design to ensure Z-Axis accuracy, V-tapered tooling should never be run faster than…
__ 6,000 rpm
__ 8,000 rpm
__ 10,000 rpm
__ 12,000 rpm
3. Countless tests have proven which of the following tool tapers to be superior in radial and axial stiffness, z-axis repeatability and performance for high speeds?
4. You should never use a cutter that has _________________ in a hydraulic holder, a milling chuck or in high speed applications.
__ Weldon flats
__ Hybrid coatings
__ Multiple inserts
__ Through-spindle coolant
5. One of the key limiting factors of a C-frame mill design is…
__ Workpiece visibility
__ Top-end rpm
__ Tool-magazine capacity
__ Y-axis rigidity
6. What is the name of the rotational axis that corresponds with the Y-linear axis?
7. The machine ____________ plays a key role in isolating and absorbing vibrations and shock from the cutting operation on the machine as well as surrounding impacts on the shop floor.
8. If the _________________ is too long on a machine, it may whip in the center, causing machine-component- and part-damaging vibrations.
__ Linear Guide Way
__ Ball Screw
__ Rack and Pinion
__ Box Way
9. Using a ________________ in your CAM program eliminates 90 degree corner moves, saving on tool and machine life, as well as increasing part quality.
__ Radial Lead-in
__ Collision check
__ Radial Step-over
10. A material’s machinability rating is a(n) _______________ value given to a particular material’s ease with which it is machined.
11. ________________________ is a measure of the linear-distance that a single point on the outside edge of the cutter is moved around the circumference as the cutter rotates in one minute.
__ Feed rate
__ Cutting Speed
__ Chip load
12. Using (an) _________________ can destroy the effectiveness and efficiency of a cut when machining ferrous alloys with coated-carbide cutters.
__ Flood coolant
__ Air blast
__ Air/Mist blast
13. When taking a depth of cut that is smaller than the full radius of the cutter, the actual amount of the cutter that is engaged into the workpiece is called the…
__ Actual Diameter
__ Actual Engagement
__ Effective Radius
__ Effective Diameter
14. A standard for maximum Length to Diameter (L:D) ratio for normal sized (not micromachining) cutters being held outside the holder, without having to slow rpm and feed, is…
15. _____ is a man-made synthetic cutter that has greater thermal resistance than diamond.
16. _____________ is the secondary ingredient used in tungsten carbide cutters that acts as a binder, and has a dramatic affect on the overall hardness of the carbide itself.
17. The ________________ of the cutter is responsible for generating the essential aluminum-oxide in a high-speed cut in ferrous materials.
18. To perform high speed machining, all holders and components should be balanced to a rating of _________ for the rpm they will be run.
19. High speed machining (which might more appropriately be called “High-Efficiency Machining”) works because the ______________ and ______________ are controlled at the point of cut.
__ Heat, Vibration
__ RPM, Feed rate
__ Loads, Limits
__ Time, Temperature
20. High-speed machining begins at 8,000 rpm and 100 ipm.
For the answer key, click here.