TEST
COMPUTER-AIDED CONTROL OF TECHNOLOGICAL EQUIPMENT
2.
NC PART PROGRAMMING
2.1. The workpart of Figure P2.1 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 3/8 in. thick.
Fig. P2.1
(a) Write the APT geometry statements to define the hole locations.
(b) Write the sequence of motion statements in APT to perform the drilling
sequence. Use a point at x=-1 and у=-3 as the target point for the FROM
statement.
2.2. Write the complete APT program for the problem of Figure P2.1. The
postprocessor call statement is MACHIN/DRILL. The drill size is 3/8-in.
diameter and the work material is machinable aluminum. Cutting speed and
feed rate are 900 revolutions per minute and 3.0 in. min.
2.3. A profile milling operation is to be performed to generate the outline of the
part in Figure P2.3. 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 1/2 in. thick.
Fig. P2.3
(a) Write the APT geometry statements to define the part outline.
(b) 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 1/8 in. of material to be cut in the
final profiling pass.
2.4. Write the complete APT program for the part of Problem 2.3. The
postprocessor call statement is MACHEN/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.
2.5. The outline of the cam shown in Figure P2.5 is to be milled using a two-flute,
1/2-in.-diameter end mill.
Fig. P2.5
(a) Write the geometry statements in APT to define the part outline.
(b) Write the motion statement sequence using the geometry elements
defined in part (a).
(c) 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/M1LL, 01. Assume that the rough outline for the
part has been obtained in a bandsaw operation. Ignore clamping
problems with this part.
2.6. The part outline of Figure P2.6 is to be milled in two passes with the same
tool. The tool is a 3/4-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.
Fig. P2.6
2.7. Write the APT program for Problem 2.2 (Figure P2.1) but use the MACRO
feature in a manner similar to that used in Example 2.6.
2.8. Suppose that the part of Figure P2.1 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 2.6). 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
2.9. Write the complete APT program for the part in Figure P2.6 using the
information supplied in Problem 2.6. The program should employ the
MACRO feature for the two passes. The postprocessor call statement is
MACHTN/MILL, 01. Inside and outside tolerances are 0.001 in. Feed rate =
3 in./min and speed = 400 rpm.
2.10.A matrix of holes are to be drilled in the manner illustrated in Figure P2.10.
The number of holes in the x direction is 5 and the number of holes in the у
direction is 7, thus making 35 holes in all. Write the APT program making use
of the MACRO feature to establish the hole coordinates.
Fig. P2.10