Why Standard EDM Pallets Make Rib Burning Harder (And How Custom Holders Solve It) 

If you've ever tried to burn long ribs around deep cavities or tall mold walls, you've probably run into the same frustration. 

Your EDM machine has the accuracy. Your electrode is correct. But suddenly, the pallet becomes the problem. 

Standard pallet systems work well for most applications. But when you need to reach deep features or burn ribs close to vertical walls, the pallet itself can get in the way of the geometry. 

The result? 

• Longer graphite electrodes 

• More vibration 

• Higher graphite costs 

• More setup time 

Sometimes the workholding, Not the EDM machine, is what's limiting what you can do. 

The problem starts when the standard pallet sits too high or takes up too much space around the electrode. 

Instead of reaching the feature directly, operators compensate by making extremely long graphite electrodes. 

Unfortunately, long electrodes create new problems of their own. 

Why Long Graphite Electrodes Create Even More Issues 

Long graphite electrodes may solve the reach problem, but they bring several new challenges with them. 

Increased graphite consumption More material means higher electrode costs. 

Reduced rigidity Long electrodes are less stable, which can affect machining accuracy. 

Longer machining preparation Bigger electrodes take longer to manufacture and inspect. 

More difficult setups Operators spend extra time checking heights and making adjustments. 

Poor repeatability If the job comes back months later for an engineering change, recreating the exact setup becomes difficult. 

The Solution Isn't a Different EDM Machine 

Many shops assume they need different tooling, or even a different machine. 

Often, all they really need is a better way to hold the electrode. 

Instead of extending the graphite, reduce the distance between the pallet and the workpiece. 

This is exactly why custom EDM holders exist. 

How a Custom Rib Holder Solves the Problem 

Rather than changing the pallet system, a custom holder works with your existing System 3R or Erowa pallet while positioning the electrode much closer to the machining area. 

The benefits show up right away. 

Burn ribs close to tall walls The holder gives the machine better access to difficult geometry. 

Use shorter graphite electrodes Shorter electrodes reduce material costs while improving rigidity. 

Standardized electrode height Every holder references the same height, so you're not remeasuring every time. 

Faster setup Mount the graphite using locating dowels and screws to cut setup time. 

Excellent repeatability The electrode can be removed, stored, and reinstalled later in exactly the same position, perfect for engineering changes or repair work. 

Real-World Application 

A customer approached Rapid Holding Systems with exactly this challenge. They needed to burn rib tracks around injection mold components where standard pallets interfered with the machining area. 

Instead of redesigning the mold or using oversized graphite electrodes, RHS developed a family of custom holders compatible with their existing System 3R pallets. 

The result: 

• Easier access 

• Less graphite 

• Faster setup 

• Repeatable positioning 

• Lower production costs 

Most importantly, they kept using their existing palletization system without changing their EDM process. 

Could This Help Your Shop? 

If any of these sound familiar, a custom EDM workholding solution may be worth considering: 

• You regularly burn seal ribs.  

• Your graphite electrodes keep getting longer.
• Tall mold walls block machine access.  
• Standard pallets interfere with machining.  
• You spend too much time rebuilding electrode setups.  
• Engineering changes mean making new electrodes every time. 
• At Rapid Holding Systems, we design custom EDM workholding solutions for applications where standard tooling reaches its limits. If you're struggling with deep cavities, tall walls, rib tracks, seal ribs, or any unique EDM challenge, our engineering team can help develop a solution that works with your existing System 3R or Erowa setup. Contact us today at [email protected] to discuss your project.