Free Trial

Safari Books Online is a digital library providing on-demand subscription access to thousands of learning resources.

  • Create BookmarkCreate Bookmark
  • Create Note or TagCreate Note or Tag
  • PrintPrint

Problems

8.1The workpart of Figure P8.1 is to be completed in an NC drill press. The outline of the part has already been completed and the five holes are to be drilled. The axis system for this sequence is to be located with the origin at the lower left-hand corner of the part. The part is in. thick.
  1. Write the APT geometry statements to define the hole locations.

  2. Write the sequence of motion statements in APT to perform the drilling sequence. Use a point at x = −1 and y = −3 as the target point for the FROM statement.

Figure P8.1.


8.2Write the complete APT program for the problem of Figure P8.1. The postprocessor call statement is MACHIN/DRILL. The drill size is -in. diameter and the work material is machinable aluminum. Cutting speed and feed rate are 900 revolutions per minute and 3.0 in./ min.
8.3A profile milling operation is to be performed to generate the outline of the part in Figure P8.3. Disregard the two holes in the part. They have already been drilled and will be used to clamp the part to the machine table. The part is ½ in. thick.

Figure P8.3.


  1. Write the APT geometry statements to define the part outline.

  2. Write the sequence of APT motion statements to perform the profile milling around the periphery of the part. Use a location 3 in. below and 3 in. to the left of the lower left-hand corner of the part as the target point for the FROM statement. Assume that the part has been cut to rough size with a bandsaw. This has left about in. of material to be cut in the final profiling pass.

8.4Write the complete APT program for the part of Problem 8.3. The postprocessor call statement is MACHIN/MILL, 05. The inside and outside tolerances on the circular approximation should be 0.001 in. The end mill is 1 in. in diameter. Speed and feed should be 400 rpm and 3.0 in./min. respectively.
8.5The outline of the cam shown in Figure P8.5 is to be milled using a two-flute, ½-in.-diameter end mill.

Figure P8.5.


  1. Write the geometry statements in APT to define the part outline.

  2. Write the motion statement sequence using the geometry elements defined in part (a).

  3. Write the complete APT program. Inside and outside tolerance should be 0.0005 in. Feed rate = 3 in./min; speed = 500 rpm. Postprocessor call statement is MACHIN/MILL, 01. Assume that the rough outline for the part has been obtained in a bandsaw operation. Ignore clamping problems with this part.

8.6The part outline of Figure P8.6 is to be milled in two passes with the same tool. The tool is a ¾-in.-diameter end mill. The first cut is to leave 0.050 in. of stock on the part outline. The second cut will take the part to size. Write the APT geometry and motion statements to peform the two passes.

Figure P8.6.


8.7Write the APT program for Problem 8.2 (Figure P8.1) but use the MACRO feature in a manner similar to that used in Example 8.6.
8.8Suppose that the part of Figure P8.1 was to be drilled, reamed, and tapped (three separate tools) at the hole locations indicated on the drawing. Write a complete APT program for this sequence using two MACRO subroutines, one to call the hole locations for the proper tool, the other to call the operation (similar to the MACRO use of Example 8.6). The tool call statement and cutting conditions for each operation in the sequence should be:

For drilling TURRET/04
 speed = 800 rpm
 feed = 2.5 in./min
For reaming TURRET/06
 speed = 500 rpm
 feed = 4.0 in./min
For tapping TURRET/02
 speed = 200 rpm
 feed = 12.5 in./min


8.9Write the complete APT program for the part in Figure P8.6 using the information supplied in Problem 8.6. The program should employ the MACRO feature for the two passes. The postprocessor call statement is MACHIN/MILL, 01. Inside and outside tolerances are 0.001 in. Feed rate = 3 in./min and speed = 400 rpm.
8.10A matrix of holes are to be drilled in the manner illustrated in Figure P8.10. The number of holes in the x direction is 5 and the number of holes in the y direction is 7, thus making 35 holes in all. Write the APT program making use of the MACRO feature to establish the hole coordinates.

Figure P8.10.



  

You are currently reading a PREVIEW of this book.

                                                                                                                    

Get instant access to over $1 million worth of books and videos.

  

Start a Free 10-Day Trial


  
  • Safari Books Online
  • Create BookmarkCreate Bookmark
  • Create Note or TagCreate Note or Tag
  • PrintPrint