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Vertical Milling Machine
This study guide will cover the major working parts, functions, and machining techniques that can be found/used on most vertical milling machines.
This study guide has been designed to directly represent the questions that will be found on the open book written assessment and as an aid for the hands-on usability assessment. Both assessments will also include questions related to standard machine shop safety and APS internal user safety guidelines.
Answering the questions found at the end of the study guide will enable the user to successfully pass the hands-on usability and open book written assessments. Study guide practice test and answers can be found at the end of the guide.
The Milling Machine uses a rotating milling cutter to produce machined surfaces by progressively removing material from a work piece. The vertical milling machine also can function like a drill press because the spindle is perpendicular to the table and can be lowered into the work piece.
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THE CONTROLS
START/STOP
The green button starts the spindle motor and the red button shuts the motor off.
Variable Motor Drive used on some Milling Machines
FORWARD/REVERSE This switch changes the rotation direction of the spindle. When the milling machine is in high range this switch is in the forward position for cutting but in low range the switch is in the reverse position. Putting the switch in the opposite position while remaining in the same range reverses the rotation of the spindle.
HAND BRAKE Also known as the spindle brake, it is used to bring the spindle rotation to a stop after the power is turned off and to aid in removing collets and chucks. The spindle can be locked by pressing or pulling the brake and then pushing it up.
SPINDLE SPEED This wheel is used to change the speed of the spindle for both high range and low range. The milling machine must be running when changing the speed.
POWER FEED The power feed uses a motor to control the motion of the longitudinal feed in either direction at various speeds. Not all of the milling machines in the shop have this option.
CROSS-FEED HANDWHEEL This hand-wheel moves the table in and out.
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QUILL STOP
The quill stop can be adjusted by hand to set a limit on the quill travel is also used to disengage the quill feed. This is useful when multiple holes have to be drilled to the same depth.
QUILL FEED LEVER AND SELECTOR These are used to activate the power feed for the quill. The selector will adjust the speed of the power feed and the lever activates the drive. The quill can be Feed down into the part or up.
DIGITAL READOUT Digital readouts (DRO) are added to the milling machines to aid in the accuracy of cuts and increase productivity. The lateral movement of the table can be measured to 2/10,000th of an inch with the readouts. Other operations the readout can perform include dividing any dimension by two, running with absolute or relative measurements, and displaying in inches or millimeters.
LONGITUDINAL/CROSS-FEED AXIS
The digital readout will display the distance traversed in both the X and Y-axis.
ZERO BUTTONS These two buttons will set their respective displays to zero. This is used after the machinist finds the edge of their part and wants to reference all of the other measurements off that axis.
INCHES/METRIC BUTTON The readout can give all measurements in inches or millimeters, by pressing this button it will switch from one system of measurement to the other.
KEYPAD Dimensions can be entered into the readout using the keypad. This can be helpful when a reference point is needed other than zero.
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Peripheral and Face Milling Techniques
Fig. 1
Fig. 2
Peripheral milling uses teeth on the outer edge of the cutter body. The surface produced corresponds to the contour of the milling cutter, which can range from a flat surface to a formed shape.
There are two different methods of peripheral milling, Conventional or Up Milling (Fig. 1) and Climb or Down Milling (Fig. 2). The figures on the left show the rotation of the cutting tool with respect to the direction of the part on the table.
In conventional milling the work is fed against the cutter, which compensates for backlash in the table. Each tooth of the cutting tool starts its cut in clean metal, prying the material off the work.
Down milling will give a better quality of work and is better suited for thin pieces of material since the cutting action forces the work into the table. This method should not be used on hard materials and the machine has to be rigid so backlash cannot occur. The cutting tool will also last longer using Down milling as long as good tool pressure is maintained.
The machines in the shop are suitable for both types of milling. If you are unsure of which method you should use ask somebody in the shop for assistance.
Face milling uses the bottom of the mill to machine the work instead of the sides. The cutting comes from the combined action of cutting edges located on the face (or end) of the cutting tool as well as the edges on the periphery. The direction of the feed with relation to the rotation is not important when using this method.
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- Stop the milling machine before ________________. A. Attempting to make adjustments or measurements. B. Trying to remove accumulated chips. C. Before opening or removing guards and covers D. All of the above.
- The milling machine is a very versatile machine tool. It can be used to ____________. A. drill, bore, and cut gears B. machine flat surfaces C. machine irregularly shaped surfaces D. All of the above E. None of the above
- It is permissible to leave the chuck key in the chuck while drilling a hole. True False
- Machine safety guards are not required to be in place most during machining operations. True False
- Always keep hands at a safe distance from moving machine parts. True False
- In conventional milling the work is fed against the cutter. True False
- Which of the pictures portrays Conventional cutting method?
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A
B
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Identify the parts of a Vertical Milling Machine.
- _________ Start/Stop Button
- _________ Digital Readout
- _________ Longitudinal Hand Wheel
- _________ Power Feed
- _________ Forward/Reverse Switch
- _________ Spindle
- _________ Table
- _________ Hand Brake
- _________ Cross-Feed Hand Wheel
- _________ Spindle Speed
- _________ Vertical Feed Hand-crank
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A
K
B C D E F G
I H
J
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Vertical Milling Machine
Study Guide
Answer Sheet
1. True
2. True
3. True
4. A
5. True
6. True
7. True
8. True
9. D
10. D
11. D
12. False
13. False
14. True
15. True
16. B
17. K
18. D
19. J
20. G
21. A
22. E
23. F
24. B
25. H
26. C
27. I
28. True
29. False
30. E
31. D
32. A
33. B
34. C
35. F
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