Quick die change is a snappy buzzphrase often associated with hard-ware including hydraulic clamps,

die rollers, bolster extensions and diecarts. However, also required to mini-mize downtime from the last good hiton one die to the first good hit on thenext die is a well-formulated, efficientdie-change process.

The beautiful thing about developinga successful quick-changeover process isthat although it does require someintense thought and effort, most of theplan can be accomplished with minimalcost. Most shops can trim changeovertime to less than 20 to 30 min. with lit-tle cost. Then, to get die changes done inas little as 5 to 20 min., capital invest-ment may be required.

All job changeovers entail similaractivities:

• Clear the press area.• Unclamp, remove and store the die.• Retrieve the new die, and locate it

and clamp it in the press.• Set up the workplace (coil line,

bins, conveyors, etc.)• Achieve first part approval.When planning a die-change pro-

cedure, entrust the people directlyinvolved with changeovers—foremen,operators, setup people—with theresponsibility of developing and imple-menting the plan. Put together a coreteam to:

• Analyze the current job-changeprocess—Videotape a few job changes.

• Identify the problem areas—Havethe team watch the video and identifythe problem areas, such as waiting 15min. for a forklift to move a scrap bin orfor someone to find and retrieve the

next die or the next coil. Breaking theprocess down into time blocks mightlook something like this:

Clear the press area 8 min.

Unclamp die 4 min.

Remove die 2 min.

Store old die and retrieve new die 10 min.

Place die in press 4 min.

Clamp die 14 min.

Adjust shut height 3 min.

Adjust air counterbalancepressure 1 min.

Set up workplace (conveyors,bins, feed-up coil stock, etc.) 20 min.

First-piece approval 10 min.

Fully man the job 5 min.

Total 81 min.

Sure, suppliers aplentystand ready to provide

stampers with a slew ofproducts designed to

expedite die changes. Butto ensure the money is

spent wisely, first carefullyplan the process and

organize the shop floor.

BY LEE ELLARD

Lee Ellard is national sales manager,Stamtec, Inc., a manufacturer of stamp-ing presses and a distributor of feed linesand quick-die-change apparatus:931/393-5050, www.stamtec.com.

The Process

A good first stepto quickening thepace of diechanges: create anefficient press-room layout, andstore dies closeand convenient tothe press area,with easy accessto the dies by thetransport vehicle.Photo courtesy ofGreen Valley Mfg.

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Tooling Technology

Quick Die Change

• Use locating pins or die guides onthe press bolster to allow consistentlyquick and accurate die setting.

• Standardize clamp pieces and storethem with the dies or on the press.

• Standardize shut heights or, as analternative, install automatic shut-height adjustment through your presscontrol. Another related time saver isuse of automatic air counterbalanceadjustment.

Shopping for QDC HardwareOnce a stamper has implemented

all or most of the above processes, con-gratulations! Now we can talk aboutwhat should be one of the last steps toimprove job-changeover efficiency—the hardware.

Control box—A simple, compact,enclosed control box mounts where it’smost convenient, and controls hydraulicdie lifters and clamps with just a keyswitch and a few illuminated buttons.

Hydraulic power units—The prop-er power unit supplies not only the cor-rect pressure, but also the number ofcircuits for the required or desired safe-ty level for equipment, tools and people.

Die lifters—Individual or array type,spring, air or hydraulically actuated dielifters lift and assist movement of dieson the press bed.

Bolster extensions—Dies can berolled from the press bed onto remov-able, pivoting, or swing-down bolsterextensions for easy retrieval by die-transport vehicles.

Hydraulic clamps—Although con-ventional clamp straps and bolts areinexpensive and adaptable, they take alot of time to set up and do not consis-tently deliver high clamping force. Abetter solution often is use of hydraulicclamps, and metalformers have a widevariety from which to choose.

• Ledge clamps can be placed manu-ally in T-slots or bolted to the bolster orslide, and clamp directly on a flat clamp-ing surface.

• Rod clamps must mount in T-slotson the bolster or slide and U-slotcutouts on the clamping surface.

Tooling Technology

Bolster extensions such as the pivot-ing type shown here allow dies to berolled on and off of the press bed foreasy retrieval by die-transport vehicles.

Develop a list of specific improve-ment goals—The above times mayseem extreme, and hopefully yourchange-overs occur more quickly than81 min., but most stampers have roomfor improvement.

Assign responsibility—Make some-one, such as the press operator, setupperson or foreman, responsible forimplementing each improvement idea.

Train the other personnel—Dur-ing the planning phase, ensure that thecore process-improvement teamreceives input from others involved inchange-overs, to engage them in theprocess. After planning, document andpost the proper procedures and conducttraining sessions for all involved.

Track the improvements—Keepwritten, posted records of before andafter results.

On the Shop Floor

An efficient pressroom layout is amust. While rearranging the shop maynot be possible, at least make it cleanand uncluttered, to allow employees tomove about quickly and safely duringjob changes. Immediately following thelast hit on the current die, move partsand scrap bins, unloaders, and otherappratus out of the way, so as to notimpede the rest of the process.

Locate staging areas for tooling, coilsand the like close to the press and haveitems prestaged in those areas well inadvance of the last hit of the current dieor coil. And, when not in a press or astaging area, store dies and coils closeand convenient to the press area, witheasy access to the dies by the transportvehicle. Keep the transport vehiclequickly available. Since the vehicle isoften a forklift, which tends to get bor-rowed for other tasks throughout theplant, consider dedicating a forklift justfor die changes. Or, buy a dedicated diecart.

Strive to have all dies designed withthe same clamping height; better yet,mount all of the dies on subplates stan-dardized for clamping height as well asleft-to-right and front-to-back dimen-sions. Standardization allows use of thesame size clamping fixture for all dies.And, with standardized subplates, fixeddie-locating pins can be used in thepress bed for quick, accurate die locat-ing. Placing of clamps can be easier orpossibly even automatic.

To standardize die mounting:• Add external blocks (such as ears)

to existing dies to obtain a standardclamping height.

• Machine die-clamping surfaces to astandard clamping height.

• Mount dies on subplates of a stan-dard thickness.

• Mount dies on subplates of a stan-dard thickness and standard dimen-sions, or perhaps develop a few standardsizes covering your complete range ofdie sizes. For example, establish a smallsubplate (60 x 30 in. perhaps), medium(84 x 48 in.), and large (144 x 60).

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Quick Die Change

• Roto-Escam clamps hide beneaththe press bed or inside the slide. Theclamping rods rotate 90 deg. andretract below the bolster and slideplate, completely escaping the die areaand allowing for clear access whenloading and unloading a die. They canclamp in a T-slot or in a specialmachined hole.

• Swing clamps release the die bytilting 30 deg. to one side, and must haveU-slot cutouts in the clamping surface.

• Traveling clamps use a driven chainmechanism or an air cylinder to auto-matically travel down a T-slot to reachthe clamping surface.

A final suggestion: For any QDChardware you purchase now, try to visu-alize how it might affect the future useof your basic pressroom equipment. Forinstance, consider any plans to add periph-eral equipment such as transfer systems,feed lines and conveyors when decidingwhat type of QDC hardware to buyand how and where to install it. MF

Metalformers have a wide variety ofhydraulic clamps from which tochoose, including ledge clamps (top),which can be placed manually in T-slots or bolted to the bolster or slide,and clamp directly on a flat clampingsurface; and rod clamps (bottom),which mount in T-slots on the bolsteror slide and U-slot cutouts on theclamping surface.

Complete this Application Form ...to collect and record most of the information needed to evaluate QDC hardware.

Estimated timetable of project (installation):� 30 – 60 Days � 60 – 90 days � 90 – 120 days � more than 120 days

Press information:MFG: _______ � New � Existing � Retrofit � RebuildModel: _______ Style: � OBI � Straightside � Other Stroke rate: _______ Shut Height: _______Press tonnage: _______Tonnage, strip force: Ram: _______Tonnage, strip force: Bolster: _______

Press bolster information:Bolster size: F - B: _______ L – R: _______ Thickness: _______Does the bed have T-slots: � Yes � NoT-Slot orientation: � F – B � L – R � Other, attach drawingDo the T-Slots run the entire length: � Yes � No, attach drawingNumber of T-slots on bed: _______ Spacing: _______Dimensions of T-Slots: _______Bolster height from floor: _______

Press ram information:Ram size: F - B: _______ L – R: _______ Thickness: _______Does the ram have T-slots: � Yes � NoT-Slot orientation: � F – B � L – R � Other, attach drawingDo the T-Slots run the entire length: � Yes � No, attach drawingNumber of T-slots on ram: _______ Spacing: _______Dimension of T-Slots: _______

Standardization program implemented? � Yes � No� Clamping height: _______� Shut Height: _______� Subplate size: _______

Die Information:Maximum Weight: _______ Upper _______ LowerDie set material: _______ Upper _______ LowerDimensions: Maximum _______ F – B x _______ L – RMinimum _______ F – B x _______ L – RTool Shut Height _______ Maximum _______ MinimumType of clamping currently used: _______If bolts, number of bolts used to clamp dies: _______ Bolt size: _______Dies are loaded from: � Front � Back � Left Side � Right SideAre dies on parallels? � Yes � NoTotal number of dies involved: _______Average number of die changed per shift:Currently: _______Objective: _______

Application information:Type of Process: � Stamping � Molding � High-Speed � High Temperature Type of Stamping: � Blanking � Drawing � Deep Draw � Forming Type of Operation: � Manual Transfer � Auto Transfer � Progressive

Die lifters:Select extension type:� Quote � Recommend � Not Required � Hydraulic � Mechanical � Rollers � Balls

Die support rails (bolster extensions):Select bolster extension type:� Quote � Recommend � Not Required � Removable � Pivoting � Drop Down

Clamping for the bolster:� Quote � Recommend � Not Required

Clamp Type:� Fixed Position � Removable

Clamping for the ram:� Quote � Recommend � Not Required

Clamp Type: � Fixed Position � Removable

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