Introduction to machining syllabus

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Milling Maching (including the CNC Mill)

A milling machine is a machine tool used to machine solid materials, including metals such as aluminum, steel, brass or plastics such as Delrin. Unlike a drill press, which holds the workpiece stationary as the drill moves axially to penetrate the material, milling machines also move the workpiece radially against the rotating milling cutter, which cuts on its sides as well as its tip. Workpiece and cutter movement are precisely controlled to less than 0.001, by means of precision ground leadscrews. This mill may be manually operated or use digitally automation via computer numerical control (CNC). Milling machines can perform a vast number of operations, from simple (e.g., slot and keyway cutting, planing, drilling) to complex (e.g., contouring, diesinking). Cutting fluid may be applied to the cutting site to cool and lubricate the cut and to wash away the resulting swarf. (cite)

See this page for an excellent tutorial on using a mill.

Safe use (cite):

  1. Wear safety glasses and long sleeves to avoid burns by hot shavings.
  2. Do not use gloves or permit loose clothing to get close to moving parts.
  3. Work must be clamped securely in a vise.
  4. Do not take climb milling cuts on the shop’s mills unless instructed to do so.
  5. Make sure cutter is rotating in the proper direction before cutting material.
  6. Before running machine the spindle should be rotated by hand to make sure it is clear for cutting.
  7. Make sure the power is off before changing cutters.
  8. Always use the proper cutting fluid for the material being cut.
  9. Never run the machine faster than the correct cutting speed.
  10. Make sure that the machine is fully stopped before taking any measurements.
  11. Always use cutters which are sharp and in good condition.
  12. Don't place anything on the milling machine table such as wrenches, hammers, or tools.
  13. Always stay at the machine while it is running.
  14. Don't take too heavy a cut or use too rapid a feed.
  15. Remove the collet tightening wrench immediately after using it.
  16. If at all feasible rig a guard or shield to prevent chips from hitting other people.
  17. Use the milling machine spindle brake to stop the spindle after the power has been turned off.
  18. Before cleaning the mill remove cutting tools from the spindle to avoid cutting yourself.

Effective use:

  1. Ensure mill will not cut vise or parallels while cutting.
  2. Run mill at low speeds when using the edge finder to avoid breaking it.
  3. Plug in the oil circulator before use.
  4. When running in CNC mode, be aware that home-finding may attempt to move the bed beyond it's excursion range.
  5. Only change speed while the mill is running,
  6. Don't change from the front gears to the back gears while the mill is running.
  7. Always check the direction the mill will turn as different outlets make the mill turn different ways.
  8. Lock the quill before engaging the power drawbar.
  9. Hold your hand under the tool when releasing tools using the power drawbar to prevent damaging end mills, your workpiece, or the vice.
  10. Be sure the table is unlocked before using any CNC control.

Metal Lathe

A metal lathe or metalworking lathe is a large class of lathes designed for precisely machining relatively hard materials. They were originally designed to machine metals; however, with the advent of plastics and other materials, and with their inherent versatility, they are used in a wide range of applications, and a broad range of materials. In machining jargon, where the larger context is already understood, they are usually simply called lathes, or else referred to by more-specific subtype names (toolroom lathe, turret lathe, etc.). These rigid machine tools remove material from a rotating workpiece via the (typically linear) movements of various cutting tools, such as tool bits and drill bits. (cite)

See this page for an excellent tutorial on using a lathe.

Safe use (cite):

  1. Wear safety glasses and long sleeves to avoid burns by hot shavings.
  2. Do not use gloves or permit loose clothing to get close to moving parts.
  3. Make sure that the chuck, driveplate, or, faceplate is securely tightened onto the lathe spindle.
  4. When removing the chuck, driveplate, or faceplate do not use machine power.
  5. When installing the chuck, driveplate, or faceplate do not use machine power.
  6. Move the tool bit a safe distance from the collet or chuck when inserting or removing work.
  7. Don't run the machine faster than the proper cutting speed – consult a speed and feed table to determine the best speed.
  8. In setting up the tool holder place it to the left side of the compound slide to prevent the compound slide from running into the chuck or spindle attachments.
  9. Do not grasp or touch chips or turnings with your fingers, but get rid of them using a blunt instrument. It is safer to turn off the lathe before clearing chips then to leave it running.
  10. Remove chuck key from chuck IMMEDIATELY after using.
  11. Don't cut work completely through when turning between centers.
  12. Turn chuck or faceplate through by hand before turning on the power to be sure there is no binding or clearance problem.
  13. Stop the machine before taking measurements.
  14. Before cleaning the lathe remove tools from the tool post and tailstock.

Effective use:

  1. Always clamp the toolbit as short as possible in the toolholder to prevent it from breaking or chattering.
  2. Always make sure that the toolbit is sharp and has the proper clearance. Ask for assistance making adjustments.
  3. If any filing is done on work revolving in the lathe, file left handed to prevent slipping into the chuck. Never use a file without a handle.
  4. If work is turned between centers, make sure that proper adjustment is made between centers and that the tailstock is locked in place.
  5. If work is being turned between centers and expands due to heat generated from cutting, readjust centers to avoid excessive friction.
  6. Set the toolbit on the centerline of your work to prevent work from climbing over tool or cutting above center and dragging.
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