Numerical Control Programming
Chapter 5
The Preliminaries of Programming

REVIEW QUESTIONS

1. Why does an N/C programmer need to be concerned with a purchase order?
   
   
2. What pitfalls can be encountered if an N/C programmer works strictly from the part drawing?
   
   
3. Why does a customer not have to buy parts that are considerably undersize or oversize when the customer's part drawing did not specify a tolerance?
   
   
4. What kinds of information that the N/C programmer needs can be found in local and general notes on a part drawing?
   
   
5. What can an N/C programmer do to assist in visualizing the geometry of complex workpieces?
   
   
6. Describe the initial decisions that have to be made by the N/C programmer at the outset of the programming process.
   
   
7. What is the most common method of holding a workpiece on an N/C milling machine?
   
   
8. What factors must be considered when selecting the N/C machine to be programmed.
   
   
9. Why do many vises lift the workpiece off the parallels when the vise is tightened? How can the lifting be prevented?
   
   
10. List the advantages and disadvantages of selecting tungsten carbide cutters over high speed steel cutters.
    
    
11. Discuss the advantages and disadvantages of 2-flute and 4-flute end mills.
    
    
12. Why cannot standard (jobbers length) drills be depended on to drill a hole where it is supposed to be?
    
    
13. How can the location of a drilled hole be assured?
    
    
14. What purpose is served by boring a hole before reaming it to size?
    
    
15. For what kinds of machining operations are ball end mills used?
    
    
16. Why cannot a ball end mill be used for heavy roughing cuts?
    
    
17. Why should a reamer remove as little material as possible?
    
    
18. Why should hand taps not be used on N/C machines?
    
    
19. What provision must be made for chips when tapping a blind hole with an N/C machine?
    
    
20. What factors must be considered when deciding on a tool change and part change location?
    
    
21. What surfaces on a casting are usually the first to be machined?
    
    
22. What are the advantages of climb milling as contrasted to conventional milling?
    
    
23. What effect can the spiral of the flutes have on an end mill that is not too securely held in the toolholder?
    
    
24. What effect can a cutter temperature increase have on the accuracy of a surface being machined?

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Updated Jan. 23, 2002
Copyright © 1988, 2002 by George Stanton and Bill Hemphill
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