National 2 Die 3 Blow

2 Die 3 Blow Image The following lesson outline details the tasks needed to be a machinist on a National 2 Die 3 Blow cold header. Some of these tasks require the trainee to explain how something works to insure they have the required understanding of the processes and are not simply memorizing procedures. All of the tasks listed will be a part of the Performance Test within each lesson. To learn more about these tests and the training process itself, see the Philosophy section.

This program was specifically designed to train setup operators of National Two-Die Three-Blow cold headers, including models 56, 89 and 1012. The instructional technique employed will enable individuals to learn to setup and operate the machines with little difficulty. Both existing personnel and new trainees can utilize these training materials to develop or improve their performance.

Lesson 1: Basic Machine Operation [ Top ]

After completing this lesson the operator will be able to:

  1. Locate, identify and explain the purpose of basic machine components:
    1. Wire Reel
    2. Wire Drawer
    3. Draw Die
    4. Wire Straightener
    5. Feed Rolls
    6. Quill
    7. Cutter
    8. Stock Gauge Tip
    9. First Transfer Fingers
    10. Pusher
    11. Dies
    12. Extrusion Punch
    13. Heading Slide
    14. Kickout Pins
    15. Second Transfer Fingers
    16. Cone Punch
    17. Finish Punch
    18. Discharge Chute
  2. Describe the operation of the wire handling equipment: how the wire is fed at the proper rate, drawn to diameter, straightened and fed into the header.
  3. Describe the cutoff process: how the required length of wire is cut off by the quill and cutter, moved to the first transfer fingers, and pushed out of the cutter.
  4. Describe the operation and sequence of steps in the heading process, including the actions of the dies, the three punches, transfer and kickout.

Lesson 2: Blank Terminology and Measuring Methods [ Top ]

After completing this lesson the operator will be able to:

  1. Explain terms commonly used for the heading process.
  2. Name various secondary operations which may be performed on blanks, such as threading, slotting, pointing and plating.
  3. Identify the blank formed at each stage in the heading process.
  4. Identify and locate features, angles, diameters and lengths commonly found on cold headed blanks.
  5. Identify blank head styles which are formed on the front face of the punch.
  6. Identify blank head styles which are formed totally or partially in the die.
  7. Identify types of cross recesses formed during the heading process.
  8. Determine allowable sizes for blank dimensions from the tolerances on a part print or drawing.
  9. Measure lengths on headed blanks using a micrometer, machinist's scale, calipers, or special gage.
  10. Measure diameters on headed blanks using a micrometer.
  11. Measure the die point diameter, die point angle and radius under the head using an optical comparator; measure the die point diameter using a micrometer.
  12. Measure blank concentricity using a chuck fixture and a dial indicator.
  13. Inspect headed blanks; identify common defects such as burrs, flashes, seams and cracks.

Lesson 3: Basic Machine Controls and Lubrication Systems [ Top ]

After completing this lesson the operator will be able to:

  1. Locate, identify and explain the purpose of the following gauges:
    1. Air Supply Gauge
    2. Lubricating Oil Sight Gauge
    3. Lubricating Oil Pressure Gauge
    4. Coolant Level Sight Gauge
    5. Feed Clutch Oil Sight Gauge
  2. Locate, identify and explain the purpose of machine components and controls:
    1. Main Power Switch
    2. Adjustable Drip Lubricators
    3. Lubricating Oil Filter
    4. Flywheel
    5. Flywheel Brake Pedal
    6. Ratchet Pedal
    7. Safety Plug
    8. Safety Bar Coolant Flow Control Valves
    9. End Of Wire Switch
    10. Stock Arm
    11. Feed Length Adjustment Knob
    12. Stock Gauge Tip Adjustment Knob
    13. Lubrication Button
    14. Brake On Pushbutton
    15. Brake Off Pushbutton
    16. Main Motor Select Switch
    17. Jog Forward and Reverse Pushbuttons
    18. Coolant Pushbutton
    19. Emergency Stop Pushbutton
    20. Feed On and Feed Off Pushbuttons
    21. Speed Selector Switch
  3. Start up the machine, turn on the lubrication motor and adjust the drip lubricators for the proper rate.
  4. Locate and inspect all pressure gauges and sight gauges; identify the proper pressure range or level for each gauge.
  5. Add way oil, feed clutch oil and coolant when needed.
  6. Determine whether the lubricating oil filter must be changed by calculating the difference between the input and output oil pressure gauges.
  7. Describe the conditions under which the machine will stop or will not start.
  8. Unplug the safety plug and place the safety bar in front of the header slide, to provide safe working conditions in the die area.
  9. Jog the header in forward while making blanks, and in reverse with no feed.
  10. Clear the work area, release the flywheel brake, start the lubrication system and the main motor, and start the machine into normal operation.
  11. Stop the machine during normal operation, set the flywheel brake and turn off the coolant.
  12. Stop the machine in an emergency situation.
  13. Identify and locate the two controls which determine the length of wire which will be fed and cut off at each cycle.

Lesson 4: The Ajax-Hogue Wire Drawer and The Wire Welder [ Top ]

After completing this lesson the operator will be able to:

  1. Locate, identify and explain the purpose of the major components of the Ajax-Hogue Wire Drawer.
  2. Describe the operation of the wire drawer, including the sequence of actions during the draw stroke and during the return stroke.
  3. Calculate the proper length of the draw stroke.
  4. Adjust the length of the draw stroke.
  5. Select the correct draw die for a job and install it in the wire drawer.
  6. Select the proper gripper spring based on the required spring tension.
  7. Install the wire guide and wire guide clamp into the draw box.
  8. Install the components of the automatic gripper assembly; set the spring tension.
  9. Weld a starter rod onto the end of the wire coil, then clean and grind the welded joint until smooth.
  10. Manually feed the wire through the drawer, then cut off the starter rod and remove any burr.
  11. Jog the header until the end of the wire is cut off; remove the end of wire to prevent jamming in the header.
  12. Explain the possible causes of the gripper blocks not gripping properly, and describe the corrective actions.

Lesson 4A: The Capstan Wire Drawer [ Top ]

After completing this lesson the operator will be able to:

  1. Locate, identify and explain the purpose of operator controls on the wire drawer.
  2. Locate, identify and explain the purpose of components of the wire drawer which feed and draw the wire.
  3. Explain how the Compensator Arm, micro-switch, and Compensator Wheel control the operation of the wire drawer.
  4. Inspect and measure a new wire coil, and compare the mill tag information to the part print to be sure it is the correct type and size.
  5. Adjust the speed of the wire drawer drum, using the Vari-Drive control, until the red feed light stays on.
  6. Prepare the coil for loading into the wire drawer by straightening the end, then grinding the first 1 1/2 feet to reduce the diameter.
  7. Remove and replace the draw die in the draw box.
  8. Run the ground end of the wire through the draw box, add drawing compound to the draw box, use the gripper chain to draw out a couple of feet of wire, then check the diameter of the wire and inspect for scoring.
  9. Draw out the first wrap of wire, release the tension by jogging the wire drawer in reverse, and position the wrap by hand.
  10. Continue drawing using the gripping chain until ten wraps of wire are on the wire drum in preparation for loading the end of the coil into the header.
  11. Install the constant contact roller if available.
  12. Release the gripper chain, cut off and smooth burrs from the end of the coil.
  13. Thread the end of the wire around the compensator wheel and into the header; jog the header through the first cutoff and remove the cutoff piece.
  14. Restock the header by welding the end of the new coil to the end of the old coil then discarding the welded portion after cutoff in the header.

Lesson 5: Setup of the Straightener and Feed Rolls [ Top ]

After completing this lesson the operator will be able to:

  1. Explain the operation of the wire straightener and the straightener rollers.
  2. Select the correct size straightener rollers based on the wire size.
  3. Remove and replace the straightener rollers.
  4. Using a piece of straightened wire, adjust the first four rollers to provide the proper straightening pressure.
  5. Adjust the last roller to align the wire coming from the straightener with the wire guide in the header.
  6. (Models 34 and 56) Explain when the coarse feed adjustment must be made based on the length of feed required.
  7. (Models 34 and 56) Adjust the coarse feed connection by attaching the connecting arm to the proper hole in the Feed Arm.
  8. Remove and clean the feed tube and wire guide, and install the proper size feed tube and wire guide based on the wire diameter.
  9. Select the proper feed rolls for a given wire diameter, then install the feed rolls using a washer for alignment if double-groove feed rolls are used.
  10. Use a piece of straightened wire clamped in the feed rolls to align the feed tube with the feed rolls.
  11. Explain the results of too little feed roll pressure and too much feed roll pressure.
  12. Adjust the feed roll pressure using the pressure bar wrench until the pressure is correct on the wire; when done there will be equal spacing between the feed box and the pressure bar at both ends of the pressure bar.
  13. Adjust feed roll pressure on machines with compressed air feed pressure control.
  14. Remove and replace feed rolls on the Model 1012 header; set the feed roll pressure using the adjusting screw.

Lesson 6: The Cutter, Quill, Stock Gauge Tip, and The First Cutoff [ Top ]

After completing this lesson the operator will be able to:

  1. Disconnect the operating lever, free the clamps, then swing the second transfer assembly out of the heading area.
  2. Remove the holddown bolt and remove the stock gauge tip.
  3. Loosen the holding nuts and remove the first transfer assembly.
  4. Remove the cutter and quill from the header.
  5. Describe the result when the quill and the cutter insert are too sharp or are dull; lightly hone a freshly sharpened quill and cutter.
  6. Explain the proper hole diameter for the cutter insert and quill based on the wire diameter.
  7. Install the cutter and quill in the header.
  8. (Model 1012 Header) Remove the quill cap; remove the pusher; remove and replace the quill, pusher and quill cap.
  9. Align the cutter to the quill using a piece of straight wire to check the alignment.
  10. Describe the possible causes for incorrect or distorted cutoff.
  11. Calculate the correct starting clearance between the cutter and quill, based on the wire diameter; adjust the clearance in the machine.
  12. Adjust the pusher for the correct length of stroke.
  13. Install and adjust the stock gauge tip.
  14. Jog the header through cutoff; measure the blank, inspect for square ends; adjust the stock gauge tip or the cutter clearance as needed.

Lesson 7: Installing The Dies and Adjusting Die Kickout [ Top ]

After completing this lesson the operator will be able to:

  1. Locate, identify and explain the purpose for components of the dies, punches, punch holders and the kickout mechanism.
  2. Describe what occurs during trapped extrusion and open extrusion, and explain the possible amount of wire diameter reduction with each type of extrusion.
  3. Loosen the cap screws and clamp screws, then remove the die cap, the dies, the kickout pin and kickout pin guide.
  4. Remove the punches from their holders. (Removal of punches and punch holders is covered in the next lesson.)
  5. Select die packing and shims for the new dies to match the height of the old dies and packing; trial fit the die stacks to make sure that they are flush with the die block.
  6. Make a kickout pin of the correct length from tool steel; peen the end of the pin.
  7. Locate, identify and explain the purpose of components of the kickout mechanisms; describe the actions of these components during the kickout cycle; identify the retracted position and the kicked position.
  8. Adjust the retracted position of the first die kickout using a sample extruded blank; make sure there is 1/16" clearance between the cam shoe and the cam.
  9. Adjust the retracted position of the second die kickout using a wire marked with the finished blank length; make sure there is 1/16" clearance between the cam shoe and the cam.
  10. Install the first die kickout pin and guide; adjust the kickout pin to extend .010" from the die face in the kicked position.
  11. Install the second die kickout pin and guide, and adjust the kickout pin to be flush with the die face in the kicked position.
  12. Clean and install the dies and packing and the die caps.

Lesson 8: The Extrusion Punch, the First Transfer, and the Trial Extrusion [ Top ]

After completing this lesson the operator will be able to:

  1. Identify and explain the purpose of the components of standard punches and of the punch mechanism in the header.
  2. Remove the punches, packing and shims from the punch holders.
  3. Select and assemble packing and shims for the new punches to match the overall length of the old punch stacks.
  4. Remove the punch holders from the machine; adjust the centering of the centering blocks to the punch holders until the side clearance is equal on both sides.
  5. Install punch holders in the machine, making sure that the pins fit into the holder and that the punch holder fits squarely against the punch rocker.
  6. Check the rocker to abutment clearances using a paper as a gauge.
  7. Adjust the punch rocker to the middle of its travel.
  8. Install the extrusion punch into the punch holder.
  9. Select the proper first transfer fingers for the shape and size of the wire; install the fingers onto the transfer head.
  10. Install the first transfer head onto the transfer arm; align the fingers with the die using a sample wire.
  11. Align the extrusion punch with the first die.
  12. Adjust the first transfer pullback timing by adjusting the first transfer cam.
  13. Trial run the header through a sample extrusion.
  14. Adjust the unextruded length of the blank using shims behind the extrusion punch.
  15. Adjust the diameter of the extruded portion of the blank by adjusting the length of the cutoff blank.

Lesson 9: Preparing The Cone Punch and The Second Transfer Assembly [ Top ]

After completing this lesson the operator will be able to:

  1. Identify components of punches and punch assemblies, including standard and sliding blow punches; explain the amount of upset possible with standard and sliding blow punches.
  2. Explain how upset material is measured in "diameters".
  3. Describe the stages in the cone blow upsetting process, and explain what takes place during each stage.
  4. Assemble and install cone blow punch assemblies.
  5. Locate, identify and explain the purpose of the components of the second transfer assembly.
  6. Install the second transfer assembly on the setup fixture and clamp; remove operating springs from the transfer arms.
  7. Remove the old fingers from the assembly, then check and adjust the arm movement until the arms swing smoothly.
  8. Select and install the fingers and install the alignment pin.
  9. Adjust the fingers to fit to the alignment pin and check the fingers for straightness.
  10. Check and adjust the timing of the fingers to the alignment pin until both fingers leave the pin at the same time; set the finger stop screw.
  11. Replace the remaining springs and position the finger opening roller using a .003" feeler gauge.
  12. Replace the transfer assembly in the header; replace and tighten the operating arm and the assembly clamps.

Lesson 10: Timing the Second Transfer and Trial Running the Cone & Finish Blows [ Top ]

After completing this lesson the operator will be able to:

  1. Align the second transfer assembly to the second die.
  2. Adjust the timing of the second transfer assembly for the earliest possible opening by adjusting the finger timing cam.
  3. Adjust the timing of the second transfer assembly for the latest possible closing.
  4. Adjust the tappet lever to 1/16" from the finger opening roller with a sample blank in the fingers.
  5. Produce a sample cone blow blank by jogging the header; check the concentricity of the head to the body.
  6. Determine the direction of a concentricity adjustment by marking a blank then completing the cone blow; adjust the concentricity of the cone punch to the die.
  7. Inspect the cone blow blank and compare to the sample; identify die underfill and other problems.
  8. Install the finish punch with packing and shims.
  9. Center the finish punch to the die.
  10. Jog the header to produce finished blanks and inspect for non-concentricity, underfill, flash or other problems.
  11. Install and adjust the air ejector to properly eject the blanks.
  12. Explain why blanks produced at jogging speed should underfill the die.
  13. Produce finished blanks by running the header at operating speed; adjust the stock gauge tip and the feed system to produce full blanks at operating speed.

Lesson 11: Operation and Part Troubleshooting [ Top ]

After completing this lesson the operator will be able to:

  1. Identify a short feed problem by inspection of blanks.
  2. Identify the following causes of short feed and describe the corrective action for each:
    1. Incorrect sized feed rolls
    2. Feed rolls slipping
    3. Out of round wire from feed rolls
    4. Worn feed rolls
    5. Slow running wire drawer
    6. Wire reel binding
    7. Kinks in wire
    8. Wire straightener rolls too tight
    9. Short feed during feed stroke
    10. Feed rolls back up after feeding
    11. Feed roll clutch slipping or jerking
    12. Wire dragging in feed tube or quill
    13. Quill and cutter not aligned
    14. Loose stock gauge tip, quill, and cutter
  3. Name the possible causes of a broken kickout pin and describe the corrective action for each.
  4. Identify the following heading problems by inspection of blanks, and explain the possible causes and corrective actions:
    1. Wire chips or slivers
    2. Inconsistent body diameter
    3. Head not on center
    4. Shiny areas or score marks
    5. Cracks or splits
    6. Distorted cutoff
    7. Double headed blanks
    8. Short blank length
  5. Name the possible causes of blanks dropping from the first transfer fingers; describe the corrective action for each.
  6. Name the possible causes of blanks dropping from the second transfer fingers; describe the corrective action for each.
  7. Name the possible causes of broken punches and punch holders; describe the corrective action for each cause.
  8. Name the possible causes for broken sliding or spring blow punches.

Lesson 12: The Relieving Die Kickout and Punch Knockout [ Top ]

After completing this lesson the operator will be able to:

  1. Explain the purpose of the relieving die kickout and describe when this attachment must be used.
  2. Locate, identify and explain the purpose of the components of the relieving die kickout attachment and describe how the attachment works.
  3. Disengage the relieving die kickout attachment when not needed for a setup. (Separate procedures are given for Models 56 and 89, and Model 1012.)
  4. Engage the relieving die kickout attachment when required. (Separate procedures are given for Models 56 and 89, and Model 1012.)
  5. Adjust the relieving die kickout attachment to provide the proper amount of relief. (Separate procedures are given for Models 56 and 89, and Model 1012.)
  6. Explain the purpose of the punch knockout and describe when this attachment must be used.
  7. Locate and explain the purpose of components of the punch knockout attachment.
  8. Disengage the punch knockout attachment.
  9. Engage the punch knockout attachment and install the knockout lever when required.
  10. Change the punch knockout cam.