Guide · November 2026

How to reduce acrylic waste on a CNC router

Acrylic is one of the most expensive sheets in a sign shop, and most of the waste happens before the router starts: in how the parts are laid out on the sheet. Here is where the material goes, and how to keep more of it.

1. Know where the waste comes from

On a typical letter job, acrylic is lost in four places:

• Spacing between parts. Every gap is at least one bit width of material turned into chips.
• Open areas the layout never filled. Corners, the space between round letters, and the inside of O, D and B.
• The last sheet. A job that needs 4.2 sheets usually means a fifth sheet that is mostly empty.
• Offcuts nobody uses again. Strips that go into a rack and get thrown out a year later.

The first three are layout problems. The fourth is a stock problem. Both can be fixed.

2. Pick the sheet size for the job, not out of habit

Acrylic is commonly sold in sizes like 48 × 96 in and cut down to smaller panels. Before nesting, check which size actually fits the parts. A set of tall letters may fit far better on a full 48 × 96 in sheet than on cut-down panels, while a job of small letters may finish on one panel with almost nothing left over. If your software can nest the same job on two sheet sizes quickly, try both and compare the sheet count.

3. Set spacing from the bit, and no wider

Extra spacing feels safe but costs material on every part. The gap only needs to be the cut width plus a small margin: about bit diameter + 0.05 in. With a 1/8 in bit that is roughly 0.175 to 0.2 in; with a 1/4 in bit, about 0.3 in. Keep a small edge margin (0.1 in or more) so outer parts do not run off a sheet that is slightly out of square.

For acrylic, many shops use a single-flute (O-flute) bit made for plastics, which clears chips well and helps avoid melted edges. Whatever bit you use, set the spacing from its real diameter.

4. Allow rotation wherever the material allows it

Clear and solid-color acrylic has no grain, so letters can usually be rotated to any angle. Letting parts turn lets an L tuck under a T, or a V sit upside down next to another V. If the faces are printed or have a direction, limit rotation to 0° and 180°, or none.

5. Use the inside of the big letters

The counters of O, D, B, P, Q and R are open sheet. Periods, hyphens, small letters and logo pieces can be cut inside them. Keep each hole with its own letter if the letter is cut as a frame, so the hole piece does not get mixed up with other parts.

6. Fill the last sheet, or plan what is left on it

The last sheet of a job is where most waste hides. Two things help:

• Move parts toward one edge. If the parts on the last sheet are packed to one side, the rest of the sheet comes off as one clean, rectangular leftover instead of a sheet full of holes.
• Record that leftover. Write down its size and material right away, so it can be used on the next job.

7. Use leftovers before opening a new sheet

Keep a simple list per material: full sheets, and leftover pieces with their length, width and count. Before nesting a new job, check whether the small letters fit on a leftover first. Using the smallest leftovers first keeps the rack from filling up with strips that are never used.

8. A real example

Here is one real channel letter job nested in NestSigns: 68 letters from one Illustrator file, on 48 × 32 in sheets, with 0.2 in spacing, 0.1 in edge margin and any rotation.

The run took 41 seconds in the browser. The leftover strip went straight into the material stock list for the next job.

Quick checklist

• Compare sheet sizes before you nest
• Spacing = bit diameter + about 0.05 in; edge margin 0.1 in or more
• Any rotation for plain acrylic; 0/180° or none for printed faces
• Small parts inside O, D and B; holes stay with their letter
• Pack the last sheet to one side and record the leftover
• Leftovers before full sheets, smallest first

More guides: How to nest channel letters to save material · FAQ