pvp2 the value of own tool sharpening

© 2010 Mate Precision Tooling. All Rights Reserved.

Value of Own Tool Sharpening

European Dealer Meeting


Sharpening Value

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– “First time right“- Cleaner cuts – nicer holes – slower tool wear – less tooling cost- No secondary “repair” work

– Less injury risk for people downstream- Press brake operators, people on assembly lines

– Quality of the final product- Quality image of your customer’s company

Is an own Tool Sharpening System really a cost …

or a VALUE ?

• Value of Correct Tool Sharpening


• Sell the Value of own Tool Sharpening System

Sharpening Value

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– Correct way of sharpening is guaranteed• Material removed during sharpening can be controlled

• Tool does not get too hot (metallurgy doesn’t change)(Insufficient coolant, Too much taken off per pass)

• Good surface finish (Grinding wheel, gradual pressure off, polishing cycle)

– Sell improved product quality and uptime• Always start with a sharp tool, may require daily sharpening

• Sharp tools can be used for a full shift


• Sell the need for onsite tool sharpening

– Spare punches and dies not always required• May be needed when tools are out for sharpening

Sharpening Value

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– Sharpen tools when it is convenient• When you have your own grinder, you can sharpen

when needed and at own convenience

– True cost of offsite sharpening• Transport time and cost

• Actual billed sharpening cost


Tool Sharpening Concept

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• Tools inspected, cleaned, sharpened, set up.

• Placed in storage cabinets until required.

• Don’t forget the tools that stay in the machine!

• After completing parts run, return all non-standard tools to tool room

• Take out and check tools if in machine too long

• All tools required for new job staged and delivered to machines

Tool Room or

Tool Storage

Machines


ValuGrind and Premia

Mate offers 2 systems

– ValuGrind• More economical – small investment

• Main benefits:• Stable construction – parallel grinding • Fixtures for various tooling styles• Powerful motor • Large grinding wheel – no dressing required • Internal coolant• Can grind shear punches

• Manual system – Result depends on operator’s attention and skills

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ValuGrind and Premia

Mate offers 2 systems

– Premia• Full-automatic system –gives always best result

• High quality surface finish

• High repeatability

• Best in class:• Touch screen control• Extended fixture system for various

tooling tyles• Complete cycle incl. spark-out• Big motor 3.3kW• Large diameter wheel• Big coolant tank; internal wheel coolant• Unique dual stage filtering system

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A little sharpening course …

Tool Sharpening


When to sharpen

R =0.25mm

Sharpen when a 0.25 mm radius forms on the

cutting edge of the punch or the die

Sharpen when a 0.25 mm radius forms on the

cutting edge of the punch or the die

When to Re-sharpen Punches and Dies

Or …- When the cutting edge reflects light- Finger nail test

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Too late !- When hole quality changes (burr increases)- When the sound of punching changes


Tools show signs when sharpening is required

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When to sharpen


Fracture betweenplate and s lug

Burr

Burr

Punch sectionw ith du ll edge

D ie sectionw ith du ll edge

S lug :

S heet :

S traight wall

S traight wall

Roll- over

Roll- over

Close-up of a burr caused by dull toolsClose-up of a burr caused by dull tools11

Where do the burrs come from?


Inspect All Tools Before Sharpening

Is this tool still worth grinding?

• Cracks in punches or dies

• Worn pins or keyways

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• Is there enough usable grind life left ?

- Different tooling styles have different grind life- Does an external grinding company understand the grind life of your tools ?


Maximum punch grind life depends on the guide system the punch is used in !

(B station punch shown)

Punch grind life: Thick Turret Tooling

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However, in most guide systems, this part is unusable because the punch cannot be adjusted further down.

Maximum Usable Grind Life = SBR - Stripper Thickness - Material Thickness - Die Penetration


Grind Life = SBR - (Stripper Thickness + Material Thickness + Die Penetration)

Punches have a bigger grind life in smaller thickness

StationMax.

ThicknessSBRUltra

A 3,8 18,9B 6,4 18,9

C / D 6,4 25,5E 6,4 26,5

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Stripper Land - Ultra A-B = 4 mm- Ultra C-D-E = 8 mm

Material Thickness

Die Penetration

100% Usable Grind Life

Mate Ultra System

Punch grind life: Ultra Tooling


Is there enough grind life left ?

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For punches used in Mate Ultra guides:

Measure punch tip to stripper

still available Grind Life = measured value

- die penetration (3mm) - sheet thickness

Must be > 0

(keep a little safety margin, e.g. 1mm)

also works for Reduced SBR punches


Mate Slug Free® Thick Turret Dies

Slug Free®

Die Components1. Punch2. Stripper3. Material4. Slug Free® Die5. Slug6. Grind Life7. Entry -- Constricting Taper8. Pressure Point9. Exit -- Relief Taper

Hole/Slug GeometryA. RolloverB. BurnishC. FractureD. Burr

Slug Free design (standard) to eliminate slug pulling

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Grind life is 3mm


Enough die grind life left ?

•Standard Thick Turret Dies:

minimum height is 27mm!

•Note: finished Mate die still has radius

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•Thick Turret standard dies: 3.0mm grind life

•Thick Turret Multitool dies: 1.5mm grind life


Sharpening of Trumpf punches

Standard and QuickLock punches :

Shear punches need to bereground more often than flat punches

Punches Grind LifeFlat 74.0mm 3.0mm

WH/RT 77.0mm 3.0mmFlat 77.0mm 6.0mmFlat 77.5mm 6.5mm

NEXT punch inserts have 3.0mm extra grind life (use of shim)

Multitool punches :- Single piece: 0.5mm

- With head: 2.0mm

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Sharpening of Trumpf dies

Trumpf recommends 1.0mm grind life only

Other suppliers too Wilson has “GL” dies with

2.5mm: clearance changes?

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Sharpening Rules – how to regrind ?

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Wheel Harness / Grit:• A2 and S7 : G-J / 46-60• M2 and M4 : D-G / 46-60

Incorrect sharpening can destroy the tool

• Always use coolant

• Use correct wheel parameters

• Grind with feed steps of 0.02mm – Repeat as required

• Demagnetize tool after regrinding– Especially in case of magnetic table– Punching itself magnetizes tools

• Break edges with oil stone– Cutting edge of punches and dies– Shoulder radius on dies

If you don’t sharpen in-house, are you sure

your tools are sharpened correctly ?

• Follow tool geometry


Good Practices

Verify Grind Life at Tool Sharpening machine- Minimum tool length indication/information charts

- Measuring gauges

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Spare Tools to Avoid Downtime- Especially of high use tools

- Sharpen off-line


Tool Sharpening Concept

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• Tools inspected, cleaned, sharpened, set up.

• Placed in storage cabinets until required.

• Don’t forget the tools that stay in the machine!

• After completing parts run, return all non-standard tools to tool room

• Take out and check tools if in machine too long

• All tools required for new job staged and delivered to machines

Tool Room or

Tool Storage

Machines


Importance of Frequent Sharpening

Improper Sharpening Total Holes Produced

Radius Formed

100,000 0.25mm 50,000 0.50mm 25,000 0.75mm 10,000 1.00mm 185,000

Total Hits 1.0mm

Total Removed

More than DOUBLE the tool life when sharpened frequently!

= Lower cost per hole!23

Proper Sharpening Total Holes Produced

Radius Formed

100,000 0.25mm 100,000 0.25mm 100,000 0.25mm 100,000 0.25mm 400,000

Total Hits 1.0mm

Total Removed


Benefits of Correct and Frequent Sharpening

• Longer tool life and lowered cost per hole

Sharpening Benefits

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• Better quality punched products– Flatter sheets

(Note: Shear punches give flatter sheets)– Cleaner holes– More accurate hole locations– More up-time on the machine

• Less stress on tools and machine

Can this be guaranteed if you don’t sharpen yourself ?


Thank you !

Any Questions ?


Keeping Your Tools Organized

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Sharpening Problems : HeatSharpening Problems : Heat

•Lack of Coolant

•Excessive Material Removal

•Wrong Grinding Wheel Choice

•Wheel Not Dressed Properly

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Improper Face Geometry

The punch was not sharpened properly. The decreased shear depth increased the flats. This caused the punch to crack due to excessive load on the punch.

Flats increased, shear decreased

New Punch28


Sharpening Problems

•Wave pattern indicates heat

•Heat changes the metallurgy of the base material and accelerates tool wear.

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