7 Costly Dummy Block Mistakes … and How to Avoid Them

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Hydraulic Press Maintenance Best Practices

Maximize Press Throughput and Extend Tool Life with These Expert Tips

Dunaway Inc. dummy block fabrication.When it comes to hydraulic extrusion presses, your dummy block might be small, but it plays a massive role in maintaining performance and quality, and avoiding costly downtime. From sealing and alignment to lifespan and maintenance, the dummy block is a wear item you can’t afford to neglect.

Here are 7 of the most common dummy block mistakes, and how to steer clear of them courtesy of your friends at Dunaway.

  1. Skipping the Preheat: A Shortcut That Costs You

Many operators assume the dummy block will heat up quickly during extrusion, but skipping preheat introduces thermal shock, reducing toughness and leading to microcracks in as little as seven days. Preheat to around 600°F (315°C) before use, either in an oven or by placing it in the center of the container for a few hours for a controlled warm-up.

  1. Ignoring Daily Visual Inspections

Aluminum buildup, wear on the land, or damaged springs (if applicable) can drastically impact extrusion quality and increase downtime. A daily visual inspection should check:

  • For buildup on the face and land
  • Spring action and mandrel movement – on blocks with springs
  • Tightness of all cap screws and bayonet lugs
  1. Letting Your Block Grow … Without Noticing

As the dummy block expands with use, it can exceed the material’s creep limits. An increase of just 0.020” in diameter may signal permanent deformation. Once blisters and high drawback loads appear, it’s already too late. Record diameter regularly. It may help to rotate the block 90° daily to equalize wear in some setups.

  1. Running a Dirty, Under-Lubricated Dummy Block

Improper lubrication leads to aluminum sticking and shortens tool life. Automatic or manual swabbing of the dummy face before each extrusion cycle is preferred. For blocks that are rebuildable, a weekly internal lube with boron nitride dry powder is recommended. Running the block through caustic once a week can also increase usable life.

  1. Using a Poor Container Seal Face

A rough or dirty container seal face causes misalignment and even breakage. Key reminders:

  • Never let the dummy block pass fully through the container.
  • Keep aluminum from building up on the die/container interface.
  • Never use acetylene torches to clean sealing faces. Use proper mechanical or chemical methods instead.
  1. Failing to Track Usage and Wear

Each dummy block should be serialized and tracked for:

  • Install date
  • Number of billets pushed
  • Outside diameter at two 90° positions

This recordkeeping allows proactive replacement before defects or catastrophic failure occur.

  1. Overlooking Attachment Issues

Whether your press uses threaded, tie-bar, or bayonet attachments, poor installation or looseness invites disaster. If the block loosens, the full extrusion force may break the attachment stud. Routine inspection and tightening – and avoiding thread damage during swap – is essential.

Trust Dunaway: Your Partner in Preventive Maintenance Excellence

Dummy block failures often cascade into larger, more expensive problems. At Dunaway, we know hydraulic extrusion presses down to every bolt and bushing. Whether you need help diagnosing extrusion issues, optimizing your tooling life or sourcing replacements, all roads lead to Dunaway.

Visit dunawayinc.com to learn more about how we keep your press – and your business – running stronger, longer.

7 Press Alignment Mistakes That Are Undermining Your Extrusion Quality

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At Dunaway, we’ve seen how something as fundamental as alignment can make or break the performance of an extrusion press. When a press is even just slightly misaligned, it does more than shorten the lifespan of components. It erodes extrusion quality, introduces inconsistencies and ultimately chips away at productivity.

Most shops know alignment matters. But too often, we see well-intentioned teams making the same mistakes – either because the symptoms are subtle or because they’re relying on outdated assumptions.

Here are seven common alignment mistakes we see in the field, what they’re doing to your press and how to fix them before the damage gets worse.

  1. Assuming the Dummy Block Will “Self-Center”

Yes, the dummy block will compensate a little. But “a little” isn’t enough. Relying on it to correct a misaligned container or stem leads to uneven skull formation, which is one of the earliest signs your alignment is off. Over time, this causes metal inflow, surface defects on extrusions and unpredictable die wear.

Fix it: Use a cold cleanout block with expansion slots to inspect skull shape daily. Uniformity is your friend.

Definition: In aluminum extrusion, the “skull” is the thin layer of aluminum oxide and other impurities from the surface of the billet that is left fused to the inside of the container liner after the extrusion process.

  1. Correcting Die-to-Container Alignment by Raising the Container

This one’s more common than you’d think. Technicians will raise the container to meet the die, especially when chasing tolerance issues, without realizing it “cocks” the container off-axis. That’s how you end up with a tilted container, off-center flow and worn container liners.

Fix it: Always align the die to the container, not the other way around. And confirm alignment at operating temperature, not when cold.

  1. Ignoring Stem-to-Container Misalignment

When the stem doesn’t enter the container straight, you get skull buildup on one side, inflow, and eventually wear on the dummy block, container liner and even the stem itself. You may also notice unusual surface issues on extrusions.

Fix it: Daily alignment checks should include inspecting the uniformity and weight of the skull. If the shape is off or the weight is trending, it’s time to act.

  1. Trusting Dummy Tool Stacks for Precise Measurements

Visual checks using dummy stacks are a more convenient way of quickly checking alignment, they often give a false sense of security and do not provide a numerically measurable value. In addition, presses at rest, without extrusion pressure and temperature, don’t behave the same as when in production.

Fix it: Use a target die or leave a butt on the die at operating conditions to get a true picture of alignment. It’s more accurate and reveals real-world misalignment.

  1. Overlooking the Effects of Heat on Alignment

Presses shift with heat – literally. If you’re checking alignment with a cold press or while the container heaters are still on but the press hasn’t cycled, you’re not seeing the actual operational geometry.

Fix it: Perform alignment checks when the press is at normal operating temperature. This accounts for thermal expansion and provides the most accurate readings.

  1. Forgetting to Recheck Tie Rod Level and Pre-Stress

Over time, foundation settling or even routine operation can knock your tie rods out of level. And once that happens, every measurement built off those reference points is compromised.

Fix it: Check tie rod level and pre-stress regularly using a machinist’s level and trammel rods. You want less than 0.0005 in/ft variation – yes, it’s that tight.

  1. Treating Alignment as a “New Press” Task Only

Alignment isn’t a one-time install procedure. Wear happens. Components shift. Operators drop heavy tooling. It all adds up.

Fix it: Establish a routine re-alignment program. Combine daily visual checks with periodic full inspections using both traditional tools and laser measurement, if available. If you’re not checking alignment at least quarterly, you’re flying blind.

Final Thought

Press alignment isn’t glamorous, but it’s foundational. A perfectly built press will still produce subpar results if alignment is neglected. And a well-maintained older press can outperform newer machines when alignment is dialed in.

At Dunaway, we understand that alignment is both a maintenance issue and quality control imperative. If you’re chasing recurring surface issues, inconsistent extrusion or unusual component wear, alignment is the first place to look.

And when you need support – from on-site alignment services to replacement components – we’re ready to help you bring it back to center.

Don’t Skip These 8 Maintenance Tasks if You Want Your Press to Run Smoothly

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At Dunaway, we’ve learned there’s a world of difference between hitting pause for routine maintenance and getting blindsided by unplanned downtime.

Most plants have the basics down – daily inspections, alignment checks, the usual suspects. But it’s those smaller maintenance tasks, the ones that slip through the cracks, that’ll bite you when you least expect it. They’re the difference between preventing premature wear and facing down a costly repair bill.

Here are 8 maintenance tasks that every extrusion plant should have on their radar, but too many don’t:

  1. Keep an Eye Out for ‘Brass Pick-Up’ on Your Guideways

When you start seeing brass transfer building up on the guideways, that’s your press telling you something’s wrong. It’s usually poor lubrication or a misalignment issue brewing. Let it go, and you’re looking at accelerated wear and alignment headaches down the road. The fix? Regular inspections and staying on top of cleaning those guideways and guide shoes.

  1. Feel Those Cylinder Rods for Heat and Bypass Issues

Here’s a simple test that tells you a lot: if your crosshead or container cylinder rods are running hot to the touch when they’re under pressure, you’ve probably got hydraulic fluid bypassing the piston head. That’s seal failure talking, and it’s not going to get better on its own. Make it a habit to check during full-load conditions. It’ll save you from much bigger hydraulic problems later.

  1. Don’t Skip Checking Tie Rod Pre-Stress Under Load

Feeling for clearance between those tie rod nuts and platen flanges is not busy work. It matters. Even a tiny 0.001″ gap means you’ve lost pre-stress, and if those tie rods fail, your entire press structure is compromised. It’s worth the time to check them periodically under full tonnage. Your press’s long-term integrity depends on it.

  1. Run a Straightedge Along That Front Platen Pressure Ring

Die alignment problems often start right here at the pressure ring. A straightedge and feeler gauge will show you distortion or “coining” that’s messing with your die stack uniformity. Catch it early and smooth it out or re-machine it before the misalignment spreads and causes bigger problems.

  1. Don’t Let Die Carrier Pocket Wear Slide

When tool holders/die saddles/die pockets start showing wear or get clogged up with aluminum buildup, your whole tooling change process takes a hit. These seemingly small issues throw off butt shearing accuracy and mess with alignment. Stay ahead of it. Inspect regularly, clean thoroughly and don’t hesitate to re-machine when needed.

  1. Keep Those Die Changer and Front Platen Contact Areas Smooth

See scoring where the die changer passes the platen? That’s not just cosmetic damage. All that friction leads to misalignment and unnecessary wear throughout your system. Grind those areas smooth and keep them lubricated. Your press will thank you with smoother operation and less stress on the components.

  1. Use Proper Fixtures or Jigs for Billet Loader Safety

Let’s be clear about this one: the billet loader area is one of the most dangerous spots for maintenance work. Never, and I mean never, rely on makeshift blocks or jury-rigged setups to block up the loader while working in the area. Invest in proper jigs, slings, or fixtures designed for safety, and always follow your lock-out/tag-out procedures. This isn’t just about preserving equipment. It’s about getting everyone home safe!

  1. Get Smart About Modern High-Temp Lubricants

The days of coating everything in graphite are long gone. Today’s precision lubricants (like boron nitride sprays and automatic dummy block sprayers) are engineered for specific applications and frequencies. Too little and you’re not getting the protection you paid for. Too much and you’re dealing with buildup issues. Work with experts who know these products to dial in the right approach for your operation.

Final Thought

Routine doesn’t mean optional. At Dunaway, we’ve seen too many plants learn this lesson the hard way. Whether you’re looking to tighten up your PM program or train your crew to spot problems before they become expensive surprises, we’re here to help you work smarter and stay productive.

Need help improving your PM program or upgrading critical components? Contact Dunaway or explore our Extrusion Press Services to learn more.

 

 

Hydraulic Press

9 Essential Maintenance Tips to Maximize the Life of Your Hydraulic Extrusion Press

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Hydraulic extrusion presses are the backbone of many aluminum extrusion plants, requiring regular care to keep them running efficiently and extend their service life. Without a well-planned maintenance routine, press downtime can quickly escalate, leading to costly repairs and lost productivity.

Here are nine key maintenance practices that will help keep your hydraulic extrusion press in optimal condition and minimize the risk of unexpected failures.

1. Perform Daily Walk-Around Inspections

Just as pilots inspect their planes before every flight, daily inspections of your press are essential for spotting minor issues before they become major problems. During these walk-arounds, check for oil leaks, monitor hydraulic system temperatures, and ensure smooth movement of key components like the main ram, container and crosshead. Keeping an eye on alignment, lubrication and small leaks is critical for extending the life of your press​​.

2. Maintain Proper Press Alignment

Misalignment in a hydraulic extrusion press can lead to uneven wear, excessive stress on components and premature failure. Ensuring that the press remains properly aligned, especially the main ram, container and stem, will prevent unnecessary strain on the machine. Regularly checking the alignment and correcting it when needed can save you from costly repairs down the line​.

3. Regular Lubrication of Moving Parts

Friction is a major enemy of hydraulic extrusion presses. Keeping all moving parts properly lubricated is key to preventing wear and tear. The press’s sliding surfaces, including the container, crosshead and die carrier guides, should be greased daily to ensure smooth operation. Use the manufacturer-recommended lubricants and avoid contamination from dirt or foreign materials​​.

4. Schedule Predictive Maintenance

Predictive maintenance leverages modern technology to identify potential issues before they cause breakdowns. Techniques such as hydraulic oil analysis, vibration monitoring and infrared thermography of electrical components can provide early warnings of wear or damage. Implementing predictive maintenance allows for timely repairs, reducing unplanned downtime and improving overall press reliability​.

5. Tighten Loose Components

Loose nuts, bolts and fittings can significantly affect press performance. Regularly check and tighten components like tie rods, guide shoes and cylinder fittings. Even minor loosening can result in misalignment or cause parts to wear out more quickly. Proper torque settings should always be adhered to as recommended by the press manufacturer​​.

6. Replace Worn Seals and Packing

Hydraulic seals and packing are vital for maintaining pressure in the system and preventing fluid leaks. Regular inspections for oil leaks or wear on cylinder rods, main ram seals and container sealing systems are crucial. Replacing seals at the first sign of deterioration will prevent hydraulic pressure loss and ensure smooth operation​.

7. Clean Critical Surfaces

Dirt and debris can wreak havoc on sensitive components of your extrusion press. Surfaces like guideways, shoes and cylinder rods should be kept clean to avoid damage from foreign matter. Regular cleaning routines, combined with the use of wipers on guideways and shoes, will help keep these surfaces in good condition, reducing the risk of scratches and misalignment​.

8. Monitor Hydraulic Fluid Condition

Hydraulic fluid is the lifeblood of your press, and its condition directly affects the machine’s performance. Regularly check hydraulic oil levels, temperature and viscosity. Overheating or contamination of the fluid can cause significant damage to pumps, valves and cylinders. Implementing routine fluid analysis and ensuring proper cooling system performance are crucial steps in maintaining hydraulic health​​.

9. Document and Schedule Maintenance Tasks

A well-organized maintenance schedule is key to ensuring that all necessary tasks are performed consistently. Maintenance logs should record daily checks, repairs and parts replacements. This history helps in adjusting maintenance frequency based on actual wear rates and provides insights for more accurate predictive maintenance planning. Ensure your team has access to detailed checklists and that all tasks are completed on schedule​​.

By following these nine best practices, you can significantly extend the lifespan of your hydraulic extrusion press and avoid costly downtime. Remember, maintaining a proactive and predictive maintenance strategy is one of the best investments you can make in ensuring your press runs efficiently for years to come.

If you have any questions, concerns or suggestions for future content, feel free to contact us directly at info@dunawayinc.com. We’re here to help!