How to Fix a Die Cutting Sandwich After Adding Too Many Shims

If you have been adding too many shims to your die cutting sandwich, you may have already noticed the warning signs: deep plate grooves, cracked cutting pads, or cuts that are worse than before. Shims are meant to fix incomplete cuts by increasing pressure, but too many shims turn a helpful adjustment into a source of machine damage. This guide explains how to recognize an over-shimmed setup and how to correct it safely.

A die cutting sandwich is the layered stack that passes through a manual or electric die cutting machine. Most sandwiches include a base platform or plate, the cutting die, your cardstock or other material, and one or more top cutting pads. The goal is to apply enough pressure for the die’s steel rule blade to cut cleanly through the material without cutting into the plates themselves. Shims are thin sheets, usually made of paper, cardstock, or plastic, that you add to the sandwich to increase total thickness and therefore pressure when a cut is incomplete.

The problem begins when one or more extra shims are added without reducing other layers. Each shim adds a small amount of thickness, but the machine’s rollers or press plates have a limited gap and a large mechanical force. Once the stack is too thick, the machine can bend its plates, emboss the die shape into the cutting pad, crush the material, or even crack the die. Fixing this requires a systematic approach rather than simply forcing the handle or motor again.

Quick Answer

Over-shimming creates excessive pressure that warps plates, embeds dies into cutting pads, and ruins cuts. Remove all shims, inspect for plate damage, then test and add back one thin shim at a time until cuts are just clean.

Understanding Why Adding Too Many Shims Causes Damage

Every die cutting machine is built to accept a sandwich within a certain thickness range. When you add too many shims, you push that stack height beyond the intended limit. The machine still forces the sandwich through because the rollers or press are mechanically driven, but the extra thickness compresses layers far more than normal. This compression does not just improve the cut; it forces the die deeper into the cutting pad and can bow the plates themselves.

Excessive pressure can show up in several ways. Cutting plates may develop permanent curve or warp, which means they no longer sit flat. The cutting pad can become deeply scored or even split along the die line. The material being cut may tear instead of cutting cleanly, or the paper may be crushed and embossed in unwanted areas. In extreme cases, the die itself can crack or separate from its backing because the force is concentrated unevenly.

It is important to understand that shims are a fine-tuning tool, not a primary pressure source. They should compensate for small variations, such as a slightly worn cutting pad or a thin paper die. If you find yourself adding more than one or two thin shims to get a cut, something else in the sandwich is likely wrong, and continuing to add shims will only make the damage worse.

Recognizing the Signs of an Over-Shimmed Sandwich

Before you try to fix the problem, confirm that over-shimming is actually the cause. The following signs often appear together when too many shims have been added to a die cutting sandwich.

• Deep cut lines in the cutting plates: The die blade should lightly kiss the cutting pad, but over-shimming forces it deeply into the plate, leaving grooves that you can feel with a fingernail.
• Warped or bowed plates: A cutting plate that was flat now rocks on a table or shows a visible curve after passing through the machine.
• Cracked or split cutting pads: Excessive pressure can split a pad along the die cut line, especially if the pad is older or made from a more rigid plastic.
• Material tearing or crushing: Instead of a clean cut, the cardstock or paper may tear, stretch, or show embossed ghost marks around the die shape.
• Difficult crank or motor strain: The machine may become harder to turn or sound strained because the stack is too thick for the roller gap.
• Uneven cuts across the die: The center of a large die might cut but the edges do not, or one side cuts more deeply than the other, often because a warped plate distributes pressure unevenly.

If you notice several of these signs after adding extra shims, stop using the machine immediately. Continuing to run an over-shimmed sandwich can cause permanent damage to your plates and even to the machine’s internal rollers or gears.

Step-by-Step Fix for an Over-Shimmed Die Cutting Sandwich

Correcting an over-shimmed setup does not require special tools, but it does require patience. Follow these steps in order to safely return your die cutting machine to normal operation.

1. Stop and Disassemble the Sandwich

Remove the sandwich from the machine. Take apart all layers and set them on a flat, clean surface. Do not try to force the sandwich through again or run it back through in the opposite direction, as this can deepen the grooves or worsen plate warping.

2. Inspect Every Layer for Damage

Examine each cutting plate for warping, deep grooves, cracks, or embedded paper fibers. Check the die for bent blades, cracks, or separation from its foam backing. Look at the material you were trying to cut to see if it shows signs of crushing. If a cutting plate is visibly warped or cracked, it should be replaced before you continue.

3. Remove All Shims

Take every shim out of the sandwich. Do not try to save one or two based on guesswork. You need a clean baseline to judge the machine’s current condition and the true cut quality without extra pressure.

4. Test with a Simple Die and Scrap Material

Build a basic sandwich with the manufacturer-recommended layers for your machine. Use a small, simple die shape and a piece of scrap cardstock of the same weight you normally cut. Run it through once and check the result. If the cut is complete and clean without any shims, your previous problem was almost certainly over-shimming.

5. Add Back One Thin Shim at a Time

If the baseline cut is incomplete, add a single thin shim, such as a sheet of standard copy paper or a thin cardstock shim, to the appropriate location. Run a new test cut with fresh scrap material each time. Do not stack multiple shims at once. After each addition, check the cut quality and the condition of the cutting plates. Stop adding shims as soon as the die cuts through cleanly without excessive plate marks.

6. Check Plate Flatness After Each Test

Before moving to the next test, place each cutting plate on a flat table and gently press the corners. If a plate rocks or shows a gap under its middle, it has started to warp. A warped plate will never give consistent pressure and must be replaced, even if the cut looks acceptable for a small die.

7. Record the Working Combination

Once you find a shim arrangement that gives clean cuts without plate damage, write it down. Note the machine, die type, material thickness, and exact shim placement. This helps you avoid adding too many shims again in the future.

Choosing the Right Shim Material and Thickness

Part of fixing an over-shimmed sandwich is understanding what kind of shim to use when a small increase in pressure is genuinely needed. Not all shims behave the same way, and the wrong choice can push you back into over-shimming quickly.

Paper shims: A single sheet of standard copy paper is one of the thinnest and safest shims for fine-tuning pressure. It adds very little thickness and can be stacked, but each additional sheet increases the risk of over-shimming if the stack becomes too tall. Use paper shims for very slight cut improvements.

Cardstock shims: A piece of thin cardstock is thicker than copy paper and provides a more noticeable pressure increase. It is useful when a die consistently misses cuts by a small margin. However, cardstock is also more likely to compress unevenly over time, so replace it if it becomes creased or worn.

Plastic shims: Some crafters use thin plastic sheets, such as transparency film, because they do not compress like paper. Plastic shims can be effective, but they are also less forgiving. A plastic shim that is too thick will quickly create excessive pressure and plate damage. If you use plastic, choose the thinnest available and test carefully.

Always use full-size shims that cover the same area as the die or the cutting plate. Partial shims placed only under one corner or one edge can create uneven pressure and cause exactly the kind of warping and incomplete cuts you are trying to avoid.

Repairing or Replacing Plates Damaged by Adding Too Many Shims

If your over-shimmed sandwich has already damaged your plates, removing shims may not be enough. Cutting plates are consumable parts in most die cutting machines, and they are designed to be replaced when they become heavily grooved or warped. There is no reliable home method for flattening a warped cutting plate permanently. Applying heat or pressing the plate under heavy weight may temporarily change its shape, but it can also make the plate more brittle or uneven.

Inspect your plates under good light. Light surface lines and shallow cut marks are normal wear and do not usually affect performance. Deep grooves that catch a fingernail, visible cracks, or a plate that no longer sits flat on a table are signs that the plate should be replaced. Using a damaged plate with a corrected sandwich can still cause uneven pressure, so replace the plate before testing further.

If you are unsure whether a plate is too damaged, do a simple flatness check on a known flat surface and compare it to a new or known-good plate. In many cases, replacing a warped plate is less expensive than repairing a machine with bent rollers or a cracked housing.

Preventing Future Over-Shimming Problems

Once you have corrected the current setup, build habits that prevent adding too many shims in the future.

• Start with the manufacturer’s recommended sandwich. Always begin with the basic layers specified for your machine and only adjust after a test cut fails.
• Change one variable at a time. Do not change the shim, the cutting plate, and the material all at once. You need to know which change made the difference.
• Keep shims organized and labeled. Store your shims flat and label them by material and thickness so you do not accidentally grab a thick stack when you meant to add a single sheet.
• Check plate condition regularly. Press the plates flat on a table before each project. If a plate is starting to warp, replace it early rather than compensating with more shims.
• Use consistent materials. Different cardstock thicknesses and die types require different pressure. Keep a small notebook of what sandwich works for each combination.

Conclusion

Adding too many shims to a die cutting sandwich is a common mistake that can quickly turn a fine-tuning tool into a source of plate damage and poor cut quality. The fix is not to force more pressure but to remove the excess shims, inspect the plates, and rebuild the sandwich methodically. By testing with one thin shim at a time and stopping as soon as the cut is clean, you can restore clean cuts and extend the life of your cutting plates. If you ever find yourself reaching for a third or fourth shim, stop and check the rest of your sandwich instead of adding even more pressure.

FAQ

How many shims are too many for a die cutting sandwich?

There is no universal number because it depends on the machine, plate condition, and die. In general, if you have added more than one or two thin paper shims and still do not get a clean cut, the problem is likely something else, such as a warped plate or an incorrect base sandwich.

Can over-shimming break a die cutting machine?

Yes, excessive pressure from too many shims can warp or crack cutting plates, and in severe cases it can strain the rollers or internal gears of manual and electric machines. Stop using the machine as soon as you notice deep plate grooves, difficult cranking, or unusual motor sounds.

What should I do if my cutting plate is already warped?

Remove the warped plate from use and replace it. There is no dependable way to flatten a warped cutting plate permanently, and continuing to use it will cause uneven pressure and poor cut quality, even with a corrected shim count.

Can I use multiple thin shims instead of one thick shim?

It is generally safer to add pressure in small increments with thin shims, but stacking many thin shims can still create over-shimming. The total thickness is what matters, so track the combined stack height and test after every change.

Why did my cuts get worse after adding shims?

Adding too many shims increases total sandwich thickness past the machine’s intended range. The extra pressure can bend plates, crush the material, and embed the die too deeply, which results in tearing and uneven cuts instead of clean lines.

How do I know if my sandwich needs shims at all?

First test the basic manufacturer-recommended sandwich with a simple die and scrap material. If the cut is incomplete on a clean, unworn cutting plate, add one thin shim and test again. If a basic sandwich works, you do not need shims for that combination.