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©2008 Mate Precision Tooling Punch Press Tool Maintenance & Ordering Recommendations.

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Presentation on theme: "©2008 Mate Precision Tooling Punch Press Tool Maintenance & Ordering Recommendations."— Presentation transcript:

1 ©2008 Mate Precision Tooling Punch Press Tool Maintenance & Ordering Recommendations

2 ©2008 Mate Precision Tooling Punch Press Tool Maintenance & Ordering Recommendations Punching Knowledge –Punching Cycle –Quality hole –Die clearance Maintenance –Tool sharpening –Spring maintenance –Turret alignment Troubleshooting & Tool Ordering Recommendations –Punch shear –Slug Pulling –Punch non-metallic material

3 ©2008 Mate Precision Tooling Punching Cycle Material Punch Die Impact Penetration Stripping Fracture Slug

4 ©2008 Mate Precision Tooling Anatomy of a Quality Hole Material Thickness Burr Height Rollover Depth Rollover Width Burnished Length Slug

5 ©2008 Mate Precision Tooling Die Clearance Definition: The size of the gap between the punch and the die. Total Die Clearance (TC) Dependent on material type and thickness Thinner material requires less clearance Thicker material requires more clearance Total clearance = Die Clearance 1 + Die Clearance 2

6 ©2008 Mate Precision Tooling Correct Die Clearance Optimum Die Clearance – Shear cracks join, balancing punch force, piece part quality and tool life.

7 ©2008 Mate Precision Tooling Tight Die Clearance Clearance Too Small – secondary cracks are created, raising punching force and shortening tool life.

8 ©2008 Mate Precision Tooling Excessive Die Clearance Large Burr Burr is not compressed and is easily removed More Rollover & Less Burnish

9 ©2008 Mate Precision Tooling Calculating Die Clearance Total Clearance = Material thickness x Total Die Clearance % (shown on chart) Die Clearance is based on type and thickness of material being punched.

10 ©2008 Mate Precision Tooling Calculating Die Clearance 0.079” x 20% = 0.016” Total Die Clearance

11 ©2008 Mate Precision Tooling Calculating Die Clearance 2.0mm x 25% = 0.50mm Total Die Clearance

12 ©2008 Mate Precision Tooling Benefits of Proper Die Clearance Longer tool life Better stripping Smaller burr height, minimum rollover More uniform holes Fewer shavings Reduced galling Flatter work pieces More accurate hole location Less wear on the machine

13 ©2008 Mate Precision Tooling When to Re-sharpen Punches and Dies R =.010” (0.25mm) Sharpen when a.010” (0.25mm) radius forms on the punch or the die

14 ©2008 Mate Precision Tooling Sharpening Rules Sharpen frequently. Provide proper face geometry. Use coolant. Coarse wheel(46). Soft wheel. (G) (Norton SGB46KVX) Radius on wheel. Minimal surface contact. Observe proper set-up practices. Establish written maintenance procedures.

15 ©2008 Mate Precision Tooling Inspect Tools Before Sharpening Fractures on dies or punches Damaged guides or slots Grind life

16 ©2008 Mate Precision Tooling Calculating Grind Life Grind Life = SBR - (Stripper Thickness + Material Thickness + Die Penetration) Stripper Material Thickness Die Penetration Usable Grind Life

17 ©2008 Mate Precision Tooling Galling Fractured or broken punches Stripping problems Poor quality holes Fast tool wear Punches with galling cause:

18 ©2008 Mate Precision Tooling Galling Remove galling from punches Consider Nitride or Maxima Run machine at slower speed Lubricate the sheet Check die clearance Causes: Heat, tight die clearance, lack of lubrication Solutions:

19 ©2008 Mate Precision Tooling Special Punch Treatments NitrideMaxima™

20 ©2008 Mate Precision Tooling Die Land Inspection Inspect die for material build up.

21 ©2008 Mate Precision Tooling Proper Wheel Dressing Correct Wrong Improper dressing can shatter the wheel

22 ©2008 Mate Precision Tooling Orientation of Wheel Wrong Right

23 ©2008 Mate Precision Tooling Importance of Frequent Maintenance More than DOUBLE the tool life when sharpened frequently! Note: Theoretical example only. Tool life will vary.

24 ©2008 Mate Precision Tooling Sharpening Problems Waves on surface are due to overheating. Heat changes the metallurgical base fo the material and speeds up tool wear.

25 ©2008 Mate Precision Tooling Sharpening Problems Undressed wheel Lack of coolant Excessive material removal Wrong grinding wheel choice

26 ©2008 Mate Precision Tooling Spring Maintenance Note: springs have a finite life and require maintenance. Be aware of the different type springs used in various tooling lines and their maintenance requirements.

27 ©2008 Mate Precision Tooling Broken Disc Springs Disc springs require lubrication. Stripping problems and guide damage can occur if springs are not maintained. If one disc spring is broken replace the entire stack. Maintain proper spring count and pattern.

28 ©2008 Mate Precision Tooling Fatigued Coil Springs Throw away length = 75% of new length. A & B station Original Style coil springs New Length Throw away length

29 ©2008 Mate Precision Tooling Misalignment-Punches Uneven punch surface wear on any one side of the tool (marking and or galling). More evident on long, narrow shapes but can happen on any shape or size tool.

30 ©2008 Mate Precision Tooling Die Misalignment ©2000Mate Precision Tooling Damaged side has marks and abrasion, evidence of being hit. Undamaged side is sharp and has no evidence of being hit.

31 ©2008 Mate Precision Tooling Thick Turret Alignment Tools

32 ©2008 Mate Precision Tooling Mate Pilot Calibration System for Thick Turret LED color indicator –Red – not aligned –Yellow – Aligned within 0.030mm –Green – aligned within 0.008mm Electronic Sensor Upper Tool Lower Tool Surface Contact Sensor

33 ©2008 Mate Precision Tooling Benefits of Proper Tool Maintenance Flatter sheets Cleaner holes Less stress on tool and machine Longer tool life More accurate hole locations

34 ©2008 Mate Precision Tooling Troubleshooting and Tool Ordering Recommendations

35 ©2008 Mate Precision Tooling Prevent Slug Pulling Use Slug Free ® dies. Eliminate magnetism in tools. Lightly dull recently sharpened tools. Increase die clearance. Maximize die penetration. Use shear. Use urethane ejectors.

36 ©2008 Mate Precision Tooling Mate Slug Free ® Die Cycle Punch penetrates the material. Slug fractures away from sheet. Punch retracts and slug is free to fall down and away through exit taper of the Slug Free die. Material held securely by stripper before punch makes contact. Pressure point constricts slug. Punch stroke bottoms out as slug squeezes past pressure point.

37 ©2008 Mate Precision Tooling Advantages of Punch Shear Tonnage reduction (up to 60%). Noise reduction. Slug control. Reduced shock loads -- tooling and machine. Flatter sheets. Improved stripping.

38 ©2008 Mate Precision Tooling Punch Shear One-way & WhisperCup ConcaveRooftopFour-Way

39 ©2008 Mate Precision Tooling Punching Non-Metallic Materials Use sharp punches and dies. Reduce die clearance by 5%-8%. Run the machine on slow cycle. Lubricate hard plastic if possible. Use Maxima™ or Nitride treated punches. If marking occurs use urethane pads. Support thin material when possible.

40 ©2008 Mate Precision Tooling Punching Thick Material +4mm Sharp punches and dies. Clearance of 25-30% of material thickness. Extra back-taper on punches. Punch to material thickness ratio of 1 minimum. 0.5mm radius on all punch corners. Inspect tools frequently for wear. Lubricate the sheet, punch and guide. Run machine on slow cycle. Use Heavy Duty tool configuration.

41 ©2008 Mate Precision Tooling Overcoming Stripping Problems Use additional back-taper on punches. Increase die clearance. Check stripping springs for fatigue. Use sharp tools. Use Heavy Duty tool configurations. Remove galling. Lubricate sheets. Use sharp punches and die. With spring tooling use larger station.

42 ©2008 Mate Precision Tooling Standard Back-taper 1/8 degree per side (1/4 degree TOTAL) Punch Size

43 ©2008 Mate Precision Tooling Reduce Galling Sharp punches and dies. Lubricate work piece. Use Maxima™ or Nitride treated punch. Increase die clearance. Adjust machine hit rate (slower). Use tool lubrication if available.

44 ©2008 Mate Precision Tooling Small Diameter or Narrow Holes When punching small diameter or narrow holes, maintain the following ratio of punch size (minimum) to material thickness: Material Aluminum Mild Steel Stainless Steel Punch to Material Ratio.75 to 1 (.5 to 1 Fully Guided) 1 to 1 (.75 to 1 Fully Guided) 2 to 1 (1 to 1 Fully Guided)

45 ©2008 Mate Precision Tooling Perimeter Calculations Calculate diagonals to determine station size Calculate perimeters for tonnage calculations A = Diagonal Dimension (Station Size) L = Hole Perimeter

46 ©2008 Mate Precision Tooling Tonnage Formula: Punch Perimeter x Material thickness x Material Tonnage Value x Material Multiplier L dimension from chart on previous slide Material tonnage values: Metric tons = Imperial tons = 25 Tonnage Calculations Material Type Material Multiplier Aluminum (soft sheet)0.3 Aluminum (1/2 hard)0.38 Aluminum (full hard)0.5 Brass (soft sheet)0.6 Brass (1/2 hard)0.7 Copper (rolled)0.57 Mild Steel1 Stainless Steel1.5 30mm round hole 3mm stainless steel Metric Tons Example: 30mm round hole in 3mm stainless steel: Tonnage = (30 x 3.14) x 3 x.0352 x 1.5 = metric tons

47 Blanking Blanking -- When the slug becomes the “good” or the “saved part”

48 Punch mm flat degree one-way shear can be used Blanking Punch Configuration

49 ©2008 Mate Precision Tooling Blanking Operations Extremely sharp punches and dies. Reduce die clearance by 5%. Determine which blank dimensions and tolerances are critical. Notify tooling provider that tooling required will be used for blanking. Use non-slug free or straight taper dies. Punches should be flat faced or with slight one-way shear. Inspect tools for wear frequently.

50 ©2008 Mate Precision Tooling Ordering Punches and Dies Punching a Hole Punch Size = Hole Size Die Size = Punch Size + Clearance Blanking a Part Die Size = Blank Size desired Punch Size = Die Size - Clearance (determined by material thickness)

51 ©2008 Mate Precision Tooling Minimum Spacing Between Holes and Forms Spacing between forms Minimum = 2 x Material Thickness between holes Minimum = 2 1/2 x Material Thickness to sheet edge Top view of sheet

52 ©2008 Mate Precision Tooling Making Straight Walled Holes Without Drilling Finished hole size is the starting point. Order Punch for Hit #2 to the finished hole size. The punch for Hit #1 equals finished hole size less 20% of material thickness. The die size equals finished hole size plus 0.1mm.

53 ©2008 Mate Precision Tooling Large Holes Without Exceeding Press Tonnage R =2.0 The customer has a Thick Turret machine with a C station auto-index. He should pierce a hole 47.0mmdiameter in mild steel T=6.0mm Suggested Solution: 1st hit-pre-pierce in the center of the 47mm hole a punch with a 25.0mm diameter. Hits 2, 3 &4-Special shape punch finish 47mm diameter with three hits. Tooling characteristics: Punch-roof top shear, Die-HD with 30% die clearance 2nd Hit 4th Hit 3rd Hit 1st Hit Special Punch Shape For Hits 2,3 & 4 R=23.5 Overlap 140 Degrees

54 ©2008 Mate Precision Tooling Customer wants to pierce a 50.0mm diameter hole in mild steel T=8mm The customer does not want to buy a special shape radius tool but wants to use standard tooling. Tool 1 Use one Square 10mm and pre-pierce along the 50mm periphery 8 holes with equal pitch. Tool 2 Finalize the hole with a 50mm flat punch 8 hits 10mm sq. Final Hit 50mm round Large Holes Without Exceeding Press Tonnage

55 ©2008 Mate Precision Tooling Large Holes Without Exceeding Press Tonnage

56 ©2008 Mate Precision Tooling Forming Tools Order Recommendations Material Type & Thickness Accurate Dimensions Spacing between forms Tool Style Punch press model Other useful information –If tool is replacement, provide Mate etch number. –Has tool been manufcatured by another supplier? –Is the design flexible? –Is the tool required for a specific station?

57 ©2008 Mate Precision Tooling Punch Press Tool Maintenance & Ordering Recommendations Summary Punching Knowledge –Punching Cycle –Quality hole –Die clearance Maintenance –Tool sharpening –Spring maintenance –Turret alignment Troubleshooting & Tool Ordering Recommendations –Punch shear –Slug Pulling –Punch non-metallic material


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