Introduction to Trak DPM SX3P

  • TRAK DPM SX3P (guarding removed)
  • Bed Type CNC milling machine

Milling machines and lathes are the machine shop workhorses. These machines are massive and powerful in order to apply the high shear forces necessary to exceed the shear strength of the materials they are designed to cut. They can precisely cut steel, stainless steel, titanium, cast iron, magnesium, aluminum, copper and brass, as well as soft materials including plastics, composites, and fine-grained woods.  Milling machines drill holes, tap threads, mill slots and edges and sculpt complex 3D shapes to precision dimensions.

Trak mills can be operated manually or by means of programs written by an operator standing right at the machine. Operating by means of a program is referred to as Computer Numerical Controlled operation, or CNC for short. CNC operation is facilitated by the convenience of using imported CAD designs to identify the dimensions of the part to be produced, and to trace the path of the part’s contours. Designers are free to let their imaginations soar when using CNC because there is no cost penalty for added design complexity. But sometimes primitive shapes are good enough – straight lines or point-to-point positioning may be all that’s required for the work piece under construction. For these, manual operation is sometimes faster and is easily accommodated on these Trak-style machines.

Students sometimes ask how long it will take to learn to operate our lathes and our mills. The question makes us smile because it’s sort of like asking how long it takes to learn to play the piano. You can produce simple but attractive pieces after only ten hours or so of practice. The longer you practice and the more challenging pieces you attempt, the more beautiful will be the work that you produce. Our advice is to just get started, but first a safety review is in order.

Safety Review for Milling Machine Operation

The key to safe milling machine operations is to wear appropriate personal protective equipment, follow instructions, and to keep a tidy work space. Hot flying chips, broken tools, and entanglement with rotating components are the chief hazards associated with milling machine operations. You must take care not to cut yourself with a tool’s sharp cutting edges. You must make sure that moving machine components come to a complete stop before making any tool adjustments. A loose tool or a loose work piece can fly out and cause injury and/or machine damage. You must hold work securely in a vise or by applying adequate force with clamps. You must take special precautions when dealing with cutting fluids. Contact with cutting fluids can cause skin and eye irritation or affect respiration. Machine guarding is one of the best ways to prevent injuries resulting from these hazards. Always close the guard doors when engaging a work piece with a cutting tool. Wash your hands often, and especially when you depart at the end of every shift.

Safety Rules of Operation

  1. Do not operate a milling machine without the assistance of an instructor or of a qualified machine shop Teaching Assistant until you have completed the Basic Training Module Ifor Prototrak Mills.
  2. Do not operate a milling machine without knowing the function of every control key, button, knob, or handle. Ask your instructor or a qualified TA for help when needed.
  3. Wear approved safety glasses (with side shields) at all times.
  4. Don’t get caught in moving parts. Before operating this machine remove all jewelry including watches and rings, neckties, and any loose-fitting clothing.
  5. Keep your hair away from moving parts. Wear a hat and constrain long hair under your hat.
  6. Protect your feet. Wear full coverage shoes – no sandals and no open toed footwear.
  7. Take off gloves before you start the machine. Gloves are easily caught in moving parts.
  8. Remove all tools (wrenches, check keys, etc.) from the machine before you start. Loose items can become dangerous flying projectiles.
  9. Never operate a milling machine after consuming alcoholic beverages, or taking strong medication, or while using drugs.
  10. Protect your hands. Stop the machine spindle and ensure that the CNC control is in the stop mode before reaching into the work area.
  11. Prevent slippage. Keep the work area dry and clean. Remove the chips, oil, coolant and obstacles of any kind around the machine.
  12. Avoid getting pinched in places where the table, saddle or spindle head create “pinch points” while in motion.
  13. Securely clamp and properly locate the workpiece in the vise, on the table, or in the fixture. Use stop blocks to prevent objects from flying loose.
  14. Use proper holding clamping attachments and position them clear of the tool path.
  15. Use correct cutting parameters (speed, feed, depth, and width of cut) in order to prevent tool breakage.
  16. Use proper cutting tools for the job. Pay attention to the rotation of the spindle: Left hand tool for counterclockwise rotation of spindle, and right hand tool for clockwise rotation of spindle.
  17. Prevent damage to the workpiece or the cutting tool. Never start the machine (including the rotation of the spindle) if the tool is in contact with the part.
  18. Check the direction (+ or -) of movement of the table when using the jog or power feed.
  19. Don’t use dull or damaged cutting tools. They break easily and become airborne.
  20. Inspect the sharpness of the edges, and the integrity of cutting tools and their holders. Use proper length for the tool. Large overhang on cutting tools when not required result in accidents and damaged parts.
  21. Use a chip brush to clear accumulated chips from the work area. Never use your fingers to clear chips.

Track DPMSX3 Machine Description

The Trak DPMSX3 milling machine is shown here with guarding removed. The milling machine relies on its massive size and powerful spindle motor (5 hp) to apply the high shear forces required to high strength materials. This milling machine is capable of manual operation or of automatic operation.

With CNC (computer numerical control) the DPMSX3 can cut pockets, angles, arcs and complex contours. A rotating cutter, called an end mill, has equally spaced teeth on its perimeter. Each cutting edge of the end mill creates a metal chip by entering and exiting the work piece. In most cases, a vise holds the work piece on the machine table during operation. Unlike the lathe, the tool on the mill rotates against a stationary work piece. Milling machines also can be used for all of the common hole-making operations as drilling, reaming, tapping, boring, and chamfering that are commonly performed on a drill press.
 

Hands-on operating instructions for beginning operators

Pre-start Safety Survey

Checklist:

Start-up procedure

  1. Turn on the 220V power switch on the back of the machine.
  2. Turn on 110V power by flipping the toggle switch on the pendant control to the up position. The control will take a few moments to boot up the software - then will display the opening main screen – For reference, the screen lists which functions are turned on.
  3. Press the arrow beneath the “Check System” mode and the screen will display the “Main Menu”

Main Screen: EDIT and RUN soft keys are grayed out when the system is first turned on. They will not function because there is no program in the CNC. Once a program is entered, the EDITkey will function. Once a program is entered and the necessary SET-UP operations are complete,the RUN key will function.

    4. Press MODE, select DRO soft key to enter Digital Readout Mode

When you select DRO (Digital Read Out) mode of operation, a new menu bar of available commands is displayed at the bottom of the control screen; Jog, Power Feed, Do One, Go To, Teach, Return Abs 0, and Tool #.

These are the commands you will use to set up your machine to produce your part.

Next steps in the startup/setup process require you to load/unload tools, set part Origin, and in put speed and feed processing parameters.

Loading and unloading a tool

Remember to fully retract spindle – and lock the quill – before depressing the power draw bar button.

Use caution holding tool to avoid sharp cutter both installation and removal.

Setting a part Origin

When you start up the Trak Mill it doesn’t necessarily know anything about your preferred coordinate system. The engineer who designed the part you’re making set a part origin which is implied by the dimensioning scheme. In the illustration, the designer has dimensioned the hole locations in reference to the intersection of the part’s left edge and top edge. You will use an edge finder to position the center of the machine spindle directly over this point and will input data to the machine control so that when it displays X0, Y0, the center of your machine’s spindle will be located directly over this point. The most common tool for accomplishing this important first task is called an edge finder. These are tools that make it quick and easy to find the edge of some object so you can Zero on it. Your Teaching Assistant will demonstrate this process for you and you should practice this repeatedly until you are comfortable with the process steps.

Appendix

What can you make on a milling machine?

ENGS 76 – Machine Design

 

 

ENGS 146 – Computer Aided Engineering

ES 25

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