ECE415 Lab 6: Turn a Shaft
Contents
1. Background Material
2. Lab Procedure
3. Check-off Sheet
4. Post-Lab Assignment
Report Due Date:
Oct. 27 2015
Electrical and Computer Engineering Department
Michigan State University
Fall, 2015
Summary of the Lab:
In this lab, you will run your NC codes from the pre-lab assignment on a Spectral
Light Turning Center to fabricate a shaft from a cylinder. Each student should mill the
shaft and turn it to the TA at the end of the lab.
Equipment for this Lab:
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Two PCs with NX 10.0 software
SAFETY GLASSES with side shields will be required for all labs. These can be
purchased at the MSU bookstore.
PC with Spectral Light Turning Center control software installed
Spectral Light Turning Center (Lathe)
One Delrin rod with length 3 inches and diameter 0.75 inch
Background Material:
1. Safety
Only trained staff/students should operate any of the machines in the lab. Training during
the semester will include operation under normal conditions, emergency situations and
potential hazards. The following basic safety statements should be followed at all times in
the lab with no exceptions.
1.
2.
3.
4.
Keep the machine and work area clean.
Keep all unauthorized people away from the work area.
Store idle tools and fixtures away from the machine.
Clamp or fixture the stock securely to the machine. Use sharp cutting tools only for
their intended purposes. Handle cutting tools carefully.
5. Use appropriate feed rates and spindle speeds while machining.
6. Dress properly. Do not wear loose clothing or jewelry.
7. Remove tools, keys, and wrenches when not in use.
8. Check for damaged tools, clamps, fixtures, and guards before using the machine.
9. Wear safety glasses or goggles while using the machine.
10. Keep your body clear of the machine’s moving parts.
11. Stay alert. Do not operate the machine when tired or under the influence of
medication, alcohol or drugs.
12. Do not remove safety guards, modify, or misuse the machine.
2. Introduction of the Spectral Light Turning Center
CNC (Computer Numerical Control) technology plays an important role in both small
and large scale automated manufacturing industries by enabling efficient and consistent
production of multiple, complex parts.
Intelitek's CNC spectraLIGHT 0400 Turning Technology introduces students to the
fundamentals of CNC turning by working with industrial-based equipment to machine
parts.
Students will experience and appreciate CNC's superiority to the time-consuming, less
accurate manually controlled machine tools.
The lab activities challenge students to develop and edit programs, and machine assorted
parts. Students gain hands-on experience in proper machine set up, cutting tool selection,
tool path simulation and machining center operation. Students design solutions for
industrial CNC turning applications with emphasis on real industrial concerns, such as
optimized programming, accurate turning and increased productivity.
3. Introduction of Lathe Operations Facing Cutting off a layer of material from the end of the stock. Facing is used to produce a uniformly flat surface, or different surface effects. Roughing
It is standard practice to remove most of the stock material with a series of rough cuts.
The rough cuts rapidly remove a large amount of material, but leave a crude finish. A
finishing pass (finish cut) is used to establish the final dimension and smooth surface.
Finishing
Finish cuts are typically light, shallow cuts made at higher spindle speeds. With a
minimal cut depth, tighter tolerances and better surface finishes are achieved.
Grooving
Plunges a grooving tool into the workpiece perpendicular to the centerline. The width and
depth of the groove are defined in the CAD drawing. If the required groove is wider than
the tool, then several adjacent plunges are programmed. Grooves are used for many
purposes. For example, when the shaft is to have an O-ring pressure seal, a groove is
machined for a standard O-ring size.
Cutoff
Cutoff is similar to the Grooving operation and uses the same tool but a slower plunge
rate. The parting tool is plunged into the workpiece and moves beyond the centerline so
that the workpiece is severed from the remainder of the stock. Sometimes a part is roughcut to length by a power hacksaw, then precisely cut to length using a lathe. The saw
leaves a rough and uneven surface. The lathe can achieve a precise length, as well as a
smooth, flat surface.
Threading
Threading operations use a special 60 degree threading tool that moves along the
workpiece parallel to the axis of rotation. Threads can be cut on the outer surface
(external threads), or on the inside of a hole (internal threads).
Threads are specified by two values: the diameter of the thread and the number of threads
per inch. For example, 0.25-20 specifies a quarter inch diameter with 20 threads per inch.
The Thread command programs a series of cuts in the same helix of the thread.
Sequence of Operations
It is essential that the previous operations are performed in a logical order. You wouldn't
want to try to do a finish operation before you do all the roughing cuts. You must first
machine the correct diameter, before turning the threads. You cannot cut an O-ring
groove on a shaft, until the shaft is turned to the correct diameter!
4. spectraLIGHT Turning Center Control Software
CAM Turning introduces students to the fundamentals of CAM programs and their use in
industry.
Students use spectraCAM software, which converts CAD drawings into numerical
control (NC) files that can be used to produce parts on a CNC turning center. The
spectraCAM software features an integrated CAD drawing package that allows a
seamless and easy working environment and includes a graphic tool path simulation
package for immediate part proofing.
Activities focus on turning-related cutting operations such as roughing, facing, grooving,
threading, cut-off procedures and code generation. The CAM Turning offers a total
solution for students to operate CAM software for programming a CNC Turning Center.
Your computer screen should appear as the picture above. The turning control software is
made up of several screens that are individually docked which means each window can
be moved and resized as needed.
The software accepts standard Fanuc-compatible EIA RS274D G&M codes that CNC
machine tools recognize.
Complete manually control of the CNC mill is possible from this control panel. This
program is also used to verify and run the cutting passes to manufacture a part.
Following is a brief explanation of each of the individual windows functions.
1. The Operator control panel below is used start and stops a program cycle manually.
Spindle speed and cutting feed rate can manually set which will override setting from the
CNC Program.
To display or hide the Operator Panel, select View > Operator Panel
Right click the Operator Panel to dock or hide it.
2. The Jog Control Panel allows you to manually move (jog) the spindle on the machine.
Jogging occurs in specific increments of speed and distance. The speed and distance
values are selected on this panel as well. You can alter the speed and distance parameters
for jogging by selecting the Jog Settings command in the Setup Menu, or by double
clicking on the Jog Control Panel.
To jog a tool:
Click the Axis button on the Jog Keypad to move the tool in the desired direction. The
tool moves at the speed and distance indicated by the Speed and Step buttons.
To move the tools continuously press the Continuous (Cont.) button. The tool will move
long as you hold the axis button. When you release the axis button the tool stops.
Double-click the Jog Control Panel to open the Jog Settings dialog box.
The X Axes are reversed when the Tool Turret is present. This is because the Tool Turret
positions the tool(s) above the work piece, and must work in a positive quadrant.
Therefore, the values of X on are reversed to make proper accommodations in the NC
program.
Caution:
With the Tool Turret installed, the Jog Control Panel allows jogging in both the positive
(backward, counterclockwise) and negative (frontward, clockwise) directions. Jogging a
complete rotation in the negative direction is allowed. However, only short positive
distances are allowed per button press. The positive motion is reserved for manually
servicing the Tool Turret. All other rotations should be in the negative direction to avoid
damage to the Tool Turret.
To display or hide the Jog Control Panel, select View > Jog Control.
Right click the Jog Control Panel to show a context-sensitive pop-up menu
3. The information displayed in the Machine Info Window varies with the particular
operation being performed:
When the machine is idle, the Machine Info Window displays information about the:
Current tool number
Tool reference point
Feed rate
Spindle speed
Number of passes made for the last program verified or run
Coordinate system being used
Current block number
Number of blocks in the last program verified or run
When you are running or verifying a program:
In addition to the above information, the Machine Info Window also dynamically
updates:
Each line of code as it is executed
Previous and next lines of code
Elapsed run time for the program.
4. The Verify Window displays a simulation of your part program (tool path verification)
when you verify a program. The appearance of the display is controlled by the settings in
the Verify Setup dialog box.
5. When a program is running or being verified, the current position of the tool is
indicated here.
When running the Control Program in Simulate mode, the Goto command will not move
the machine to the specified coordinates. It will simulate movement, showing the tool
moving to those coordinates in the Position Window.
6. When you open an existing NC part program file, or create a new one, the program
appears in a program edit window.
Note:
If a Program Edit Window is locked, the background of the edit window is gray. In the
locked position, no edits can be made. If the window is unlocked, the background is
white.
Lock an NC program by choosing Edit > Lock.
7. Tool Types and configuration of the tool turret
Materials and Construction
Cutting tools are usually made from hardened steel or carbide. Carbide is more brittle
than steel, but has a longer tool life.
Tools are often ground to shape by the operator to suit a particular cutting application.
The clearances ground behind cutting edges must be adjusted for the type of material the
tool will cut and the direction the tool will move along the work piece.
Insufficient clearance behind the cutting edge will cause the tool to rub. Excessive
clearance will produce a ridged or wavy finish due to the small length of tool edge in
contact with the work piece.
Side Tools
Side tools are used to face-off the ends of shoulders or to make facing cuts in the surface
of a work piece held in a chuck. They may also be used as turning tools.
Right side (or right-hand) tools feed from right to left and are used to reduce the work
piece to a desired diameter. The shape of the cutting edge and the clearance (behind the
point between the end of the tool and the work piece) determine the surface finish of the
work piece. Rough cuts are made in small increments until the tool is within
approximately 0.010 inch (0.25mm) of the desired diameter. Final cuts are made at slow
feed rates with a very shallow depth of cut.
Left side (or left-hand) tools feed from left to right. Side tools cut very flat surfaces and
can be used to produce a part with an exact thickness .
Boring Tools
Boring tools are used to enlarge or modify a drilled or cored hole in a work piece.
Clearance must be maintained behind the cutting point of the tool.
A slow feed rate and frequent tool withdrawals are required with boring tools because
chips cannot freely escape from the hole. Depth of cut and feed rates must be reduced to
avoid chatter. The tool should not be driven deeply into a hole. When boring a hole where
a flat bottom is required, stop the feed at least 0.002 inch from the desired depth of the
smaller hole being bored out.
Profiling Tools
Profiling tools are quite popular in CNC applications because they can cut on both sides
and in both directions. A profiling tool cuts in the same way as a turning tool.
Threading Tools
Most threads are cut with a 60 o threading tool. For fine threads, the tool can be ground to
a sharp point. For coarse threads, you may wish to radius the point. A threading tool is
used for external threading operations. An inside threading tool is used for internal
threading, like on a nut.
Sharpening Tools
A cutting tool must be sharpened regularly to preserve its original cutting angle and
shape. Longer tool life will be obtained from cutting edges if they are finished with a
small oilstone. Only the cutting end and sides of the tool should be ground as required.
Never grind the top face of the tool.
The following is the tool turret setup for the tools and position for the ECE415 lab. You
have used this information in the Pre-lab to define two tools to generate the proper NC
code for the lab.
A. Tool Position 1
B.
Tool Position 3
C. Tool Position 5
Lab Procedure:
1. Login and starting the spectraLIGHT software
On each bench you are able to toggle the keyboard and mouse between the mill and lathe
computers by select the Scroll Lock button twice.
Login in to the left screen which is the lathe, using your Engineering username and
password.
Go ahead and start the spectraLIGHT software by selecting Start > All Programs >
CNCBase for SLT > CNCBase for spectraLIGHT 0400 Turning Center.
2. Home the lathe
The first operation that needs to be completed every time you start a new project is to
home the lathe. This puts the lathe into a know state and programming will run from this
information. If you forget or try to perform an operation that required the lathe to be
home the software will pop-up a warning window and you will be asked to perform a
home operation before continuing. To home the lathe, select the following from the
control software window. Setup -> Set/Check Home->Move to Home
Note:
Different from the mill where both the cutter and table are moved to a know position the
lathe will only home the tool turrent so that it knows what cutter is in which position. The
rotating stock will always be in the same place as it cannot move in any direction.
Select Tools > Operate Tool Turret. The Operate Turret box appears.
Click Home, The turret will turn to the Home position.
Click Done to exit the dialog box.
3. Manually move the cutter
From time to time it is necessary to move the part manually. This can be done by using
the Jog Control Panel on the right. Care must be taken when moving the cutter assembly
manually in order not to run the cutter into the part. Go ahead and carefully move the mill
using the Jog Panel. Notice how the cutter moves in relation to the X and Z buttons. Try
the different speeds and step controls in order to get a feel of how the part is moved. You
will need to be able to manually move the part around in order to set the zero position for
your part. Once you feel comfortable moving the cutter around, go ahead and re-home the
cutter assembly and proceed to the next step.
4. Load the Delrin Rod to machine
At this time go ahead and get a Delrin rod from your TA to load into the lathe.
The door and vice for the lathe are controlled by software and pneumatics. In order to
open the door and the vise to load and un-load parts you need to select the following from
the left hand side of the lathe control software.
Door
Chunk
The top button on the control bar turns the spindle
on and off.
The second button, that looks like and electrical
outlet, controls the door and selecting it will open
and close the door.
The third button, that looks like and electrical
outlet, controls the chuck and selecting it will
open and close the chuck on your stock.
Rob1 and Rob2 buttons are robot controls and we
will use them later in the semester.
The rest are indicators and show the current status
of that action.
If you hover over the button a short explanation
will appear for each button/action.
5. Set the Point of Origin
Use the Zero Position command in the Setup Menu to reset the point of origin to the
current tool position.
Since the tool length and the work piece position on the cross slide may vary from one
tooling setup to another, the zero position must be initialized each time the setup is
changed. You can also define the origin using the tool radius as an offset value.
For example, the length of the delrin rod is 3 inches. Since part of the rod will be inside
the chuck, the useable length we assume is 2 inches. Moreover, the diameter for the rod is
0.75 inch. In this case, we can set up the origin in the following steps (the first tool will
be used as a reference tool):
 Jog the tool to the left side of the rod;
 Using the smallest jog steps possible, carefully jog the tool to just touch the side
of the rod. Use a piece of paper between the tool tip and the stock to determine
when the tool touches. (You have done this in the milling machine)
 Select Setup > Set Position. Enter the useable length 2 for Z;
 Now Jog the tool onto the top of the rod, and use a piece of paper to determine
when the tool touches the rod;
 Select Setup > Set Position. Enter the radius of the rod 0.375 for X.
6. Load sample CNC program
From the lathe control software select File > Open.
Navigate to the folder containing the NC code for the shaft you have generated in the Prelab. Select the file and click Open.
7. Verify your part
Using tool path verification, you can check for programming errors before running a part
program.
Select Program > Verify.
The Verify Program dialog box appears.
If the verification looks correct, ask the TA to check your setup before you run
the machine.
8. Running the NC Program for the shaft
WARNING!
Unless you are in simulate mode: Before executing any program
be sure all safety precautions have been taken:
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Be sure the safety shield is closed.
Wear safety glasses.
If anything goes wrong, immediately press the Emergency
Stop button.
After reviewing the Safety Checklist, select the Run/Continue command from the
Program Menu. The Run Program dialog box appears.
Make sure that the Start Line box is set to line 1 of the program.
Click the Run Settings button. The Run Settings dialog box appears.
Make desired changes in the Run Settings dialog box, then select OK.
Click the Run Program button to begin running your program.
When a program is running at least one lab partner needs to be watching the lathe in
order to press the emergency stop button in case of an unsafe condition or if the lathe is
not cutting the part as intended.
After the part is finished open the safety shield and remove the finished part. You should
then home the mill and clean your area of all cuttings.
Emergency stop button!!!!
Stopping the machine in case of emergency
WARNING!
In the case of an emergency ALWAYS use the emergency stop button!
It is essential to stop the machine immediately if an emergency arises. The Emergency
Stop button is located on the front panel of the machine; it has an oversized red cap.
Pushing in the Emergency Stop button terminates the part program and completely
disables the spindle, even if the computer is turned off.
To stop the machine for an emergency:
Push in the emergency stop button.
Notify You TA that you had to push the Emergency Stop Button and wait for
further instructions.
To resume operation of the machine:
Be sure the cause of the emergency is resolved. This will need to be verified by
your TA.
Close the safety shield.
Pull the emergency stop button out.
Home the machine.
Reset the tool position.
Note:
You must home the machine after pressing the emergency stop button.
9. Clean up and Home the machine
After the part is finished open the safety shield and remove the finished part. Write your
Name at the back of the block and turn it to the TA. You should then vacuum out the
machine, clean your area of all cuttings, home the machine.
After cleaning everything, please logoff the machine instead of shutting it down!!
ECE 415: Lab 6 Turn a Shaft
Check-off List
Student Name:
PID:
---- As you go through the steps, demonstrate you results to the TA and ask him
to sign at the end of each step
---- Attach this check-off sheet to the end of your lab report.
Step 1: Login and open the Turning software
____________________
Step 2: Home the Lathe
____________________
Step 3: Manually move the part/cutter
____________________
Step 4: Load the Rod to machine
____________________
Step 5: Set the point of Origin
____________________
Step 6: Load CNC program
____________________
Step 7: Verify the part
____________________
Step 8: Run the NC Program
____________________
Step 9: Clean up and Home the machine
____________________
Grades for this lab
100
Pre-lab
20
Lab Performance
15
Part Quality (Dimensions)
15
Lab Report
50
Lab Report Questions:
1. Summarize the lab: In your own words, summarize the goals of the lab, expected
outcomes, and achieved outcomes (your actual results/accomplishments). Discuss
your learning experiences for the lab. (5 points)
2. During the setup process before machining, we used a piece of paper and tool No.1
to set the origin at point O shown at the following left figure.
Recall that in the Turning Tutorial for the Pre-lab, we entered -0.15 (page 4 of the
tutorial, third figure) for the z-axis when we set up the machine coordinate system
(MCS). Why do we choose the number negative 0.15? In the MCS set up, we have
also changed the directions of the coordinate system’s axes by choosing the setup
shown in the above right figure. Why do we need to make such a change? (10 points)
3. The TA gave you a draft drawing for a shaft design (or self design) at the end of this
Lab. This is what you will fabricate using the same turning machine for the next lab.
Do the following:
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Use NX to first build the solid model according to the dimensions in the draft
drawing.
In the solid model, please also draw the blank geometry, which is a cylinder with
usable length 2 inches and diameter 0.75 inch. You can change the transparency
of the bland geometry by going to Edit/Object Display. Then you can change the
translucency to around 80.
Follow the CAM turning handout used for the pre-lab to generate the NC code for
next lab.
This is an individual task, and each student needs to finish one part. Attach the
solid model and shop documentation to your report (Please do not attach the
NC code). (30 points)
4. Feedback of the lab: discuss any suggestion for the lab to help us improve the lab
experience. (5 points)