©2008 mate precision tooling punch press tool maintenance & ordering recommendations
TRANSCRIPT
©2008 Mate Precision Tooling
Punch Press Tool Maintenance & Ordering
Recommendations
Punch Press Tool Maintenance & Ordering
Recommendations
©2008 Mate Precision Tooling
Punch Press Tool Maintenance & Ordering Recommendations
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
©2008 Mate Precision Tooling
Punching CyclePunching Cycle
Material Punch
Die
Impact Penetration
StrippingFracture
Slug
©2008 Mate Precision Tooling
Anatomy of a Quality HoleAnatomy of a Quality Hole
Material Thickness
Burr Height
Rollover Depth
Rollover Width Burnished
Length
Slug
©2008 Mate Precision Tooling
Die ClearanceDie ClearanceDefinition: 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
©2008 Mate Precision Tooling
Correct Die ClearanceCorrect Die Clearance
Optimum Die Clearance – Shear cracks join, balancing punch force, piece part quality and tool life.
©2008 Mate Precision Tooling
Tight Die ClearanceTight Die Clearance
Clearance Too Small – secondary cracks are created, raising punching force and shortening tool life.
©2008 Mate Precision Tooling
Excessive Die Clearance
Excessive Die Clearance
Large BurrBurr is not compressed and is easily removed
More Rollover & Less Burnish
©2008 Mate Precision Tooling
Calculating Die ClearanceCalculating 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.
©2008 Mate Precision Tooling
Calculating Die ClearanceCalculating Die Clearance
0.079” x 20% = 0.016” Total Die Clearance
©2008 Mate Precision Tooling
Calculating Die ClearanceCalculating Die Clearance
2.0mm x 25% = 0.50mm Total Die Clearance
©2008 Mate Precision Tooling
Benefits of Proper Die Clearance
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
©2008 Mate Precision Tooling
When to Re-sharpen Punches and Dies
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
Sharpen when
a .010” (0.25mm)
radius forms on the punch or the die
©2008 Mate Precision Tooling
Sharpening RulesSharpening 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.
©2008 Mate Precision Tooling
Inspect Tools Before SharpeningInspect Tools Before Sharpening
Fractures on dies or punches
Damaged guides or slots
Grind life
©2008 Mate Precision Tooling
Calculating Grind LifeCalculating Grind Life
Grind Life = SBR - (Stripper Thickness + Material Thickness + Die Penetration)
Stripper
Material Thickness
Die Penetration
Usable Grind Life
©2008 Mate Precision Tooling
GallingGalling
Fractured or broken punches
Stripping problems
Poor quality holes
Fast tool wear
Punches with galling cause:
©2008 Mate Precision Tooling
GallingGalling
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:
©2008 Mate Precision Tooling
Special Punch TreatmentsSpecial Punch Treatments
Nitride Maxima™
©2008 Mate Precision Tooling
Die Land InspectionDie Land Inspection
Inspect die for material build up.
©2008 Mate Precision Tooling
Proper Wheel DressingProper Wheel Dressing
Correct Wrong
Improper dressing
can shatter the wheel
©2008 Mate Precision Tooling
Orientation of WheelOrientation of Wheel
Wrong Right
©2008 Mate Precision Tooling
Importance ofFrequent Maintenance
Importance ofFrequent Maintenance
Improper Sharpening Proper Sharpening Total Holes Produced
Radius Formed
Total Holes Produced
Radius Formed
100,000 0.25mm 100,000 0.25mm 50,000 0.50mm 100,000 0.25mm 25,000 0.75mm 100,000 0.25mm 10,000 1.00mm 100,000 0.25mm
185,000 Total Hits
1.0mm Total Removed
400,000 Total Hits
1.0mm Total Removed
More than DOUBLE the tool life when sharpened frequently!
Note: Theoretical example only. Tool life will vary.
©2008 Mate Precision Tooling
Sharpening ProblemsSharpening Problems
Waves on surface are due to overheating.
Heat changes the metallurgical base fo the material and speeds up tool wear.
©2008 Mate Precision Tooling
Sharpening ProblemsSharpening Problems
•Undressed wheel
•Lack of coolant
•Excessive material removal
•Wrong grinding wheel choice
©2008 Mate Precision Tooling
Spring MaintenanceSpring MaintenanceNote: springs have a finite life and require maintenance.
Be aware of the different type springs used in various tooling lines and their maintenance requirements.
©2008 Mate Precision Tooling
Broken Disc SpringsBroken 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.
©2008 Mate Precision Tooling
Fatigued Coil SpringsFatigued Coil Springs
Throw away length = 75% of new length.
A & B station Original Style coil springs
New Length
Throw away length
©2008 Mate Precision Tooling
Misalignment-PunchesMisalignment-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.
©2008 Mate Precision Tooling
Die MisalignmentDie 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.
©2008 Mate Precision Tooling
Thick Turret Alignment ToolsThick Turret Alignment Tools
©2008 Mate Precision Tooling
Mate Pilot Calibration System for Thick Turret
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
©2008 Mate Precision Tooling
Benefits of ProperTool MaintenanceBenefits of ProperTool Maintenance
Flatter sheets
Cleaner holes
Less stress on tool and machine
Longer tool life
More accurate hole locations
©2008 Mate Precision Tooling
Troubleshooting and Tool Ordering
Recommendations
Troubleshooting and Tool Ordering
Recommendations
©2008 Mate Precision Tooling
Prevent Slug PullingPrevent 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.
©2008 Mate Precision Tooling
Mate Slug Free® Die Cycle
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.
©2008 Mate Precision Tooling
Advantages of Punch ShearAdvantages of Punch Shear
Tonnage reduction (up to 60%).
Noise reduction.
Slug control.
Reduced shock loads -- tooling and machine.
Flatter sheets.
Improved stripping.
©2008 Mate Precision Tooling
Punch ShearPunch Shear
One-way & Whisper Cup
Concave RooftopFour-Way
©2008 Mate Precision Tooling
Punching Non-Metallic Materials
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.
©2008 Mate Precision Tooling
Punching Thick Material +4mm
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.
©2008 Mate Precision Tooling
Overcoming Stripping Problems
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.
©2008 Mate Precision Tooling
Standard Back-taperStandard Back-taper
1/8 degree per side(1/4 degree TOTAL)
Punch Size
©2008 Mate Precision Tooling
Reduce GallingReduce 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.
©2008 Mate Precision Tooling
Small Diameter or Narrow Holes
Small Diameter or Narrow Holes
When punching small diameter or narrow holes, maintain the following ratio ofpunch 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)
©2008 Mate Precision Tooling
Perim
ete
r Calc
ula
tion
s
Calculate diagonals to
determine station size
Calculate perimeters for
tonnage calculations
A = Diagonal Dimension
(Station Size)
L = Hole Perimeter
©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 = 0.0352
Imperial tons = 25
Tonnage CalculationsTonnage 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 Steel 1
Stainless Steel 1.5
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 =
13.93 metric tons
BlankingBlanking
Blanking --When the slug
becomes the
“good” or the
“saved part”
Punch 3.0-5.0mm flat
1.5-3.0 degreeone-way shear can be used
Blanking Punch Configuration
Blanking Punch Configuration
©2008 Mate Precision Tooling
Blanking OperationsBlanking 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.
©2008 Mate Precision Tooling
Ordering Punches and DiesOrdering 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)
©2008 Mate Precision Tooling
Minimum Spacing Between Holes and Forms
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 edgeTo
p v
iew
of
sh
ee
t
©2008 Mate Precision Tooling
Making Straight Walled Holes Without Drilling
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.
©2008 Mate Precision Tooling
Large Holes Without Exceeding Press Tonnage
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
©2008 Mate Precision Tooling
Customer wants to pierce a 50.0mm diameter hole in mild steel T=8mmThe 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
Large Holes Without Exceeding Press Tonnage
©2008 Mate Precision Tooling
Large Holes Without ExceedingPress Tonnage
Large Holes Without ExceedingPress Tonnage
©2008 Mate Precision Tooling
Forming ToolsOrder Recommendations
Forming ToolsOrder 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?
©2008 Mate Precision Tooling
Punch Press Tool Maintenance & Ordering Recommendations
Summary
Punch Press Tool Maintenance & Ordering Recommendations
SummaryPunching 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