ET 449 LABORATORY  4

                Introduction to THREADS: MILLING

PURPOSE:

The purpose of this laboratory exercise is to familiarize students with the basics of producing threads on a CNC milling machine.

Parts completed in laboratories 3 and 4 will later be used to complete the 4th exercise in laboratory 5.
During lab 4, A 3D parametric file will be used to create a 2D dxf file.  OneCNC
will be used to make editorial changes, create the appropriate tool paths for drilling or pocketing, creating a CNC program
to thread mill the center hole, simulate the program execution, and produce a final part on the HAAS vertical milling machine.
Illustration 1 shows a view of the part to be completed, and an engineering drawing is shown in Illustration 2.
 
 

Illustration 1: Threaded Hub

                                                                                              ILLUSTRATION 2:  THREADED HUB

OBJECTIVES:

After completing this laboratory exercise you should be able to do the following:

Manipulate a 3D model and generate a 2D dxf file.
Import the dxf file into OneCNC
Translate the axis for part zero
Select required geometry for drill cycles
Select required geometry for pocketing operations
Select required geometry for contouring
Select required geometry and produce a thread milling tool path
Select the appropriate tooling for machining operations
Set required feeds and speeds
Generate required tool paths
Run a simulation to verify part cut
Download a CNC program to the HAAS controller
Set a “Part zero” work plane
Set tool offsets
Operate the HAAS vertical mill to produce a drill index profile and hole pattern.

TERMS:
 

OneCNC
dxf
XFA file
NC file
Part Zero (origin)
Tooling Set up
Transform
Drill Operation
Pocketing
Thread milling
Contour Operation
Verify Operation

Laboratory Preparation

1.  Study the drawing shown in Illustration 1, and identify the geometry to be machined. Note that the part produced
in THIS  Lab will be used for exercise 5. The first step for this lab will include importing the required dxf file into
OneCNC.   Window around the part geometry and select COPY/MOVE/.  When
prompted for MOVE FROM,  select the left endpoint of the top object line.   When prompted to enter MOVE TO,
select KEYBOARD, and make sure the coordinates are set to zero.  Press enter and the origin should then be located
center of the part as shown below.   NOTE:  AS AN ALTERNATIVE, G54 MAY BE SET AT INTERSECTING LINES
OF TANGENCY AT THE TOP AND LEFT SIDE OF THE PART.
 

                                    Illustration 2: Moving to the ORIGIN (at center of part).
 

Illustration 3: Moving to the ORIGIN (traditional G54 location).

2.  Next select the holes to be drilled.  For this lab, determine the appropriate tap drill for a 3/4-10 and drill
     at least 1/4 inch smaller.
 

3.  Next pocket the hole to the minor diameter required dimension make sure to check the appropriate
     dimensions for a 3/4-10 UNC thread.

4.  The final operation will be performing a thread milling operation using a singe point 60 degree
      internal threading tool as shown in Illustration 4.

                                                  Illustration 4: Thread Milling Set Up.
 

5.  After completing all machining operations for required geometry,  the final step will be creating
     CNC code completing the threaded part.  The cutting tool for this operation will be
     a single point internal threading tool.   Complete the following:

    From the menu, select NC>2 axis > THREAD MILL.
    Select the geometry to be machined
    Click done when finished selecting the geometry
    When the TOOL INFORMATION tab appears on your screen, click the SELECT TOOL button
    Select the single point threading tool  icon.

    OBSERVE THE TOOL NUMBER> Change the tool number  to 7.
    Make sure you change all of the following the the same tool number:
            TOOL NUMBER
            LENGTH OFFSET
            DIAMETER OFFSET
            WORK OFFSET

    Change the SURFACE SPEED  to 200.
    Change the FEED RATE to 10.0
    Change the PLUNGE RATE TO  2.0

    Select the COMMENTS tab and enter comment for the thread milling operation.
 

Next, select the cut control tab.

Set  the IN Z depth of cut to  .700.
Set the required RPM and FEED RATE to synchronize and produce a pitch of .1
Click DONE when complete.

 
Next, click on the OPERATIONS MANAGER icon.
SAVE YOUR WORK
At this point, you can run a graphical simulation; however you must set up the stock.
Right click on the BLUE HIGHLIGHTED NC PROJECT
Select EDIT SETUP INFORMATION
Select the STOCK tab
Select the cylinder tab
Change the Z coordinates to 0,-.500
Set the rotation about the Z axis
Select ADD then click OK
Next, click on the RED CHECK MARK icon
Change the VIEW to ISOMETRIC
RUN THE SIMULATION
 

You can now save the file as LAB4.txt on a floppy disk and transfer to the HAAS CNC mill.
Check with your instructor for assistance and RUN THE PART.

SUBMIT A LAB REPORT USING THE STANDARD LABORATORY FORMAT.

NOTE:  LAB WRITE UP AND DELIVERABLES ARE DUE AT THE BEGINNING OF
            THE NEXT SCHEDULED LABORATORY SESSION.