The road from turret punch press operator to guru

It all starts with good coaching

The FABRICATOR March 2019


Punching is in a moment of transition,especially as fiber lasers continue to populate more shop floors across the sheet metal industry.The fiber laser has taken on more and more cutting work,which in turn is changing how fabricators use the punch press.No matter how fast and effectively a laser cuts,it still can't create knockouts,卡片指南,百叶窗,and other forms.

Metcam's operation reflects this trend.The precision metal fabricator in Alpharetta,Ga.has upped its fiber laser investment in a big way,but four turret punch presses still play an important role in the fabrication value chain—and it needs people who know how to get the most out of them.

According to Joey Howard,fabrication manager,most of Metcam's punch operators came to the fabricator without any experience.They began as helpers and other entry-level positions,expressed interest in punching,and learned the craft on the job.

怎样,确切地?As Howard and others explained,training happens in stages.But before anything else,good training requires good coaches.

Developing Coaches

Walk through Metcam's punching department and you might find a lead operator coaching someone about sheet loading (for its remaining manually loaded machine),part inspection,or perhaps showing someone how to grind off a tab quickly and effectively.Senior operators and department leads follow a process to show rookies the ropes,with the hope of turning a greenhorn into a guru over time.

But developing a training process is just half the picture.The other half involves identifying the right people for punching in the first place.Like at many shops,cross training abounds at Metcam.Some press operators move over to the lasers and vice versa.Such flexibility in high-product-mix fabrication has become essential.

But Metcam managers also know that it absolutely needs people with process expertise.They probably work with multiple fabrication technologies,but they excel at one.

As Howard explained,the fiber laser has changed the typical profile of the cutting machine operator.In the era of CO激光切割,the best operators took a hands-on approach to their jobs.They cleaned the cutting heads;changed out lenses;and checked the laser gas pressure and mix,风箱,mirror alignment,还有更多。If a person loved working on old cars,he more than likely loved learning and maintaining a CO激光。

The same can be said today for the turret punch press.Really getting to know a punch machine involves tool inspection,锐化,checking (and rechecking) the turret layout,还有更多。像CO一样激光器,冲床,especially an older one,draws in people who love hands-on work.

The modern fiber laser is a different animal."Our new fiber lasers require a lot more work on the control itself,rather than hands-on work with a physical tool," Howard said.

Tool organization at Metcam is intuitive.Even the greenest of greenhorns should know where to retrieve a 2-in.square punch and die.

He added that this doesn't necessarily reduce the number of people who can be cross-trained to excel at both.The fabricator simply takes work styles into account to ensure a job is a good fit.If a rookie punch operator likes the hands-on work,the machine setup and part inspection routines,he or she has a better chance of turning into a seasoned operator,who in turn could become a technical guru who enjoys coaching the less experienced.

Stage One: Loading and Inspection

Say a few greenhorns at Metcam show up for their first day in the punch press department.What is their first day like?

安全之后,the department's priority is consistent quality."We'll first tell them how to stay safe and the safe zones [around the machine]," Howard said.

After that a senior operator shows them how to load sheets on the manual-loading machine,origin the system,and ensure the sheet is clamped correctly.After that he shows them the shaker tabs;how to remove parts effectively;how to identify which tabbed parts require deburring (most of the company's telecom work,for instance) and which do not;and walks them through effective deburring techniques.

Most significant,operators are taught to inspect parts for quality problems.操作员翻转部件和骨架,inspects for burrs and other telltale signs of problems,and in so doing teaches the rookies about what exactly causes those problems.例如,an excessive burr could have a variety of causes,but common ones include a die that needs sharpened or an improperly set clearance between the punch and die.A burr on one side of a hole could 英国williamhillpoint to a dull die,while a concentric burr all the way around could 英国williamhillpoint to an excessively large punch-die clearance.

These problems are very rare,霍华德说,but they do happen,and senior operators do their best to prepare newbies for the worst.All this in turn opens the discussion about maintaining proper tool clearances for different material thicknesses and the importance of regular sharpening.At this stage rookies don't attempt to fix these problems.They're just being introduced to them and learning how to identify them so they can flag more experienced operators to direct the corrective action.

Stage Two: The Basic Setup

Once the rookies grasp the basics and know how to keep typical jobs running,they learn how to set up those jobs and maintain the tooling.The first jobs rookies set up likely will use a combination of common round and square punches.Much of the turret might already be in place as the "standard" setup for the job mix at hand;all rookies need to do is fill in the gaps.

Starting at a centralized crib,tools are staged for the next job in kits,during which an employee checks the tools carefully against the layout sheet.With a coach's help,the rookie will insert the punches in the correct position following a detailed setup sheet (a critical component for bringing new operators up to speed) showing the tool order via the tool number and even pictures of the tool profiles.

In doing these setups,operators learn how to check a turret to ensure they have the correct order and orientation of both the punches and dies.And during the rookies' first setups especially,their coach is never far away.

"During those first days,we might catch certain basic problems,like cross-tooling,where you have the top at 90 and a bottom at zero [or vice versa]," said Howard."The machine would crash if we let it run."

Ken RoosteeMetcam's shop planner,英国williamhillpoints to an entry in the company's tooling database.

They learn the basics of matching punches and dies,and the fact that one punch might go with one of several dies depending on the material grade,厚度,and tool clearance required.And they learn to inspect and sharpen tools as necessary (using "high-tech" techniques like the fingernail test;if an edge fails to dig slightly into a fingernail,it needs sharpening).To maximize tool life,operators learn when machining 0.005 in.够了,or when 0.010 in.might be necessary.

When they do remove tools,they also learn to inspect the condition of the key,which orients the tool in a certain direction (0,90,180度,等等)。"That key is a wear item," Howard said."You don't want your guide to wear first.You'll see the key wear first." If keys start to wear without being replaced,the tool eventually will start to turn slightly in the station—which is not a good thing for punching precision.

At this stage the senior operators teach less experienced people to look for subtle (though again very rare) problems that slipped through programming."Some tools might have a high die sitting next to another tool with a high die,which may mark a part," Howard said,adding that in this case,the lead person could show the problem to the rookie,tell him why it's a problem,then take corrective action by editing the program and communicating with the programming department.

Howard emphasized that these edits are a rarity.Editing a program on the floor is never ideal,and newer software can flag some problems in programming.But to grow in their careers,punch operators need to learn to catch the occasional problems and master the careful process of correcting them at the machine.(顺便说一下,if an operator does make an edit,those changes do not flow back to the turret programmer database.As with so many sheet metal processes,in punching there are many ways to skin a cat.Controlling the flow of information ensures master programs aren't changed without careful review.)

Stage Three: Special Tools

With more cutting jobs moving to the laser,a greater percentage of Metcam's turret punch jobs entail something that even the world's fastest fiber laser simply can't do: forming.Form tools introduce a host of variables,not the least of which is material thickness variation.在这里,operators make good use of a test strip on the near end of the sheet,where they cycle the punch to ensure the form tools are set at exactly the right height.

Universal knockout tools illustrate just how precise these special punch setups need to be.Most knockout tools Metcam uses have bottoming plates;也就是说,they form the knockout via a bottoming operation designed for a specific material thickness and application.But the shop also uses a few universal knockouts without bottoming plates.在这些情况下,a programmer would set an M code (which form tools and other specials require) so that the bottom surface of the knockout is exactly twice the material thickness minus 0.005 in.This causes the knockout tabs to be just the right amount into the material thickness;太多,and the knockout will be difficult to knock out,太少了,and it will fall out on its own prematurely.

当然,material thicknesses can change from lot to lot.It's not uncommon for a universal knockout job to be set just right on certain material,but then need to be adjusted when the same job is run with a different lot of material several weeks later.Experienced operators at Metcam can spot these issues,and senior operators know what to do at the turret and at the control to fix the problem.

Howard said that only the most senior operators set up certain challenging form jobs,often because one misstep can cause a very expensive tool to crash.That bottoming knockout tool is just one example.If an operator uses a specific bottoming knockout with the wrong (thicker) material thickness,a very costly tool crashes immediately.


"Our punch department is rock-solid.I really mean that."

That was Ken Roostee,Metcam's shop planner who develops punch programs and puts together those detailed setup sheets.He's not one to 英国williamhillpoint out false praise.A California native,he's worked with Amada punch machines for decades—Wiedemanns before that,hand cranks and all—and learned the art of laying out templates.

The punched emboss on the left is a critical design element,yet the piece still can be formed on the panel bender.After panel bending,in which the hold-down tools flatten the emboss,a separate press "re-forms" the emboss to the proper dimension.

When Roostee arrived in the Southeast in 2004,he knew what to do."I didn't go to the want ads.I called the machine shops around Atlanta." Those machine shops,当然,continually do work for area fabricators."I told them I was a sheet metal guy,and I asked them about who they thought were the best sheet metal shops.They told me about Metcam,我在这里。”

It would be fair to say that Roostee is a guru when it comes to punching.He's built a tool database for the company's vast library,including a long list of form tools that include everything from lance and form tools to card guides.A link on the screen brings him to a PDF of the tool drawing.

Roostee nests manually ("freestyle," as he calls it) to achieve optimal material use as well as the most stable process."If I want a group nest that includes parts needed for an assembly,I plan a standard nest,then put together PDFs [with pictures of the tools and parts],which spell out exactly how a job should go."

He 英国williamhillpointed to a picture of a keyhole punch tool on the setup sheet."The tool spec says [to insert it at] 180 degrees,and your experienced guys would know that,but your greenhorns wouldn't.So we put a picture,showing exactly how the tool should be oriented in the machine.

"You'll see the arrangement of tools with boxes showing which parts they are.你看到了

we've incorporated a revision here [from a customer].So we corrected one piece and reprocessed it,and then we redocument the tools to make sure the sheet flows right and the turret flows right.And because that's all documented,when we run this part again,we can just duplicate it."

He clicked through a file structure that has turret layouts for a particular machine and nesting program components,each sharing the same file name so they're never mismatched.He then pulled up a recent nest layout and 英国williamhillpointed to one edge of the sheet,with flats for a box plus several end caps and brackets,a set destined for the same assembly."Look at that—no trim."

As Roostee sees it,the better a programmer visualizes a turret layout and learns the craft of nesting,the more a fabricator can get out of a punching operation.Each of the turret's three rows has a tool placed there for a reason."You want good flow during the operation," he said.

The more that programmer learns about the intricacies of punching,the more error-free those punch programs become once they reach the floor.例如,that nesting layout with minimal trim on one side ran with perfect stability,thanks to a strategic punching sequence and microjoints.

After mentioning "microjoints," Roostee paused and switched course."Tabbing is an art unto itself," he said.材料类型,张力的,and thickness factor into them,as well as the punch sequence and sheet size.Parts punched last on a large sheet can become unstable,hence the need for a support rib up the middle of the nest layout."And you need the right microjoints at just the right angles so that the web is supported."

He then paused quickly again and drew an arc.At the peak of that arc is 0.060-in.碳钢,with about a 0.012-in.微关节。On the left is thin material which requires thinner microjoints,but thicker joints also require thinner microjoints,hence the arced shape of Roostee's line."If you try to put a 0.012-in.-thick microjoint on 10-gauge,you'd have to whack the part with a heavy hammer to get it out of the skeleton.但又一次,how many microjoints are there?If you add an extra joint for support,you can make each a little smaller."

Ken Roostee pulled up a sample setup sheet that calls out tooling order by number and includes small pictures of special tools,like keyhole shapes,that need to be placed in a certain orientation.

Roostee works with senior operators across the shop to design innovative approaches.On the floor he 英国williamhillpointed to a batch of cut blanks staged to be formed on the company's newly acquired Prima Power panel bender.空白显然来自一个转塔冲头,the telltale sign being the embossed form.

The problem was the emboss's location,right where the panel bender's hold-down tools would clamp down to form the edge flanges.Why not form this piece on the press brake?Because of the piece's corner geometry,brake tools couldn't access all the required bends.This is a high-volume part,同样,so forming speed is of the essence.最快的,most stable way to form the piece is on the panel bender.

但是,再一次,what about that embossment from the punch press,which the panel bender's tools flattened?It turns out that it's a critical design component,so eliminating the punch form wasn't an option.那现在呢?

在这里,a quick secondary operation comes to the rescue.Roostee and his team designed a custom tool on a separate press that quickly locates and "re-forms" the embossment,resulting in a quality part that falls well within specified tolerances.

The Joy of the Puzzle

The punching career (and any career in this business,真的)从基础开始:学习安全和操作基础,which basically involves the ability to keep a well-programmed job running reliably.It eventually blossoms into a job centered around creative thinking.

Spurring that creativity is that intimate process knowledge gained over decades of experience.At this writing,Roostee isn't far from retirement.事实上,this industry is full of Roostees,those gurus who soon will be heading out the door—not gone,but not available at a moment's notice either.仍然,if shops foster environments full of good coaching,their knowledge doesn't have to leave with them.





制造者is North America's leading magazine for the metal forming and fabricating industry.The magazine delivers the news,technical articles,and case histories that enable fabricators to do their jobs more efficiently.制造者has served the industry since 1971.

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