PURPOSE:Manual CNC Programming:ET 349 LABORATORY 3
Determining Cutter Compensation and Tool Path Coordinates
for A Drill Index and Angle Gage
The purpose of this laboratory exercise is to provide
a framework for understanding the basic trigonometric
calculations and cutter compensation for manual CNC
programming. A drill index and angle gage will be
produced for laboratory exercises 3 and 4. Illustration
1 shows a view of the project to be completed. The
activity for laboratory 3 will include making a preliminary
outer profile cut as depicted in Illustration 2.
OBJECTIVES:
Illustration 1: Drill Index and Angle Gage
After completing this laboratory exercise you should be able to do the following:
Calculate the required coordinates for machining specified angles
Determine the appropriate cutter compensation to profile a part
Write a manual CNC program
Download a CNC program to the HAAS controller
Set a “Part zero” work plane
Set tool offsets
Operate the HASS vertical mill to produce a drill index profile
TERMS:
Cutter compensationLaboratory Preparation
Offset calculations
Theata
MACH3
ASCII file
Absolute Coordinate System
NC “Words”
G Codes
M Codes
Part Zero Work plane
Tool offset
Graphic Simulator
HAAS Controller
1. Study the drawing shown in Illustration 1,
and identify the geometry to be machined. Note that pre-sized
stock will be provided by the lab instructor.
The first step for this lab exercise will determining tool path
coordinates. Tool path coordinates for
NORMAL lines (horizontal and vertical) can be found by offsetting
the part object lines by a value equal to the radius
of the cutter to be used. For this laboratory exercise,
a 1/8 inch diameter, 2 flute end mill will be selected.
Illustration 2: Outer part profile
For this laboratory exercise you will have to determine the tool path for a 1/8 inch end mill to make the
profile cut as show in illustration 2. Anglular cuts are required for 30 degrees,45 degrees, 60 degrees, and 118 degrees.
The easiest way to begin the calculations is to construct lines parallel to those marked in green as shown in
Illustration 3. However offset the new construction lines by the radius of the cutter as depicted in green
(in this case 1/16 inch).
Illustration 3: Line offsets representing cutter compensationNOTE: Part zero is located in the upper left corner of part and fixture (common point). Intersection points of green lines indicate coordinate values needed to write the CNC program. These lines for the profile cut correspond to the outer profile tool path of the part to be machined.
Calculate the coordinate values for the lines marked as follows and record in the spaces provided below
(Note: attach a copy of manual calculations as an appendix to the lab write up). Starting in the upper left
hand corner of the part (0,0), determine the end point of the first line (A). This coordinate will become the
beginning of line B. Continue CLOCKWISE around the part and determine the endpoint coordinates for
each of the remaining lines and record below.
Once you have determined all the coordinates for the profile cut, make the plunge cut with 1/8 diameter end mill as indicated in illustration 2.
J ___________________ _____________________
K ___________________ _____________________
L ___________________ _____________________
M ___________________ _____________________
Use the STANDARD TEMPLATE as shown below, and complete the required code for your program. Make sure to comment your program thoroughly. Comments are generated by placing parentheses around the relative text as shown for
(Program Name) in line 2.%
O0001 (Program Name)
N05 G20 G40 G49 G54 G80 G90 G98
N10 M06 T01
N15 G43 H01
N20 M03 S1200
N25 G00 X0.0 Y0.0 (M08)
N30 G00 Z.2
N35
N40 (PLACE CODE HERE)
N45
N50
N97 G91 G28 Z2.0
N98 M05
N99 M30
%Procedure:
1. Calculate the required tool path coordinates.LABORATORY REPORT FORMAT
5. Using Notepad (or MS Word, plain ASCII text), write a program to produce the
designed part.
6. Save the file as a plain ASCII text file.
7. Using MACH3, run a simulation of the part to be machined to verify the tool path.
8. Upon verification, save the file using the following:
Name format: Filename.txt (note: no more than 8 characters for filename).
9. Next Step will be machining the part. Notify the instructor or lab assistant
When you are ready to transfer the part to the HAAS machine.
10. Load the 1/8 End Mill (with assistance from the lab instructor) in position 1.
11. Load a 1/4 inch end mill into tool position 2.
12. Mount a stock blank in the fixture/vice.
12 Verify the workplane coordinates for G54.
13. Touch off and set tool work off-sets for each tool.
14. Download your program to the CNC machine.
15. Graphically simulate your program for verification.
16. Have your instructor approve the program and set-up.
17. Run the CNC program to produce the drill index.
18. Have your instructor sign the lab completion form.
10. Write a brief lab report using the following format shown below,
and turn in deliverables as indicated.
Title:
Your Name:
Lab Section:
Date:
Purpose:
Objectives:
Procedure:
Results (deliverables)
1. Part sketch and tool path coordinate calculationsConclusion/Discussion: (Discuss the outcomes and describe any difficulties encountered.
2. Set-up Sheet
3. Program Listing
4. Printed tool path simulation
4. Actual Machined Part
5. Quality Sheet showing actual measured dimensions. You may use the sketch below to create your
required quality sheet.
Make recommendations for changes for improvements).NOTE: LAB WRITE UP AND DELIVERABLES ARE DUE AT THE BEGINNING OF
THE NEXT SCHEDULED LABORATORY SESSION.
