"How thick can it cut?" has two layers of answers. The first is Z-axis travel: 100mm on the Carbon Pro and 80mm on the Carbon Lite, which looks like far more than enough. But the real limit is set by the second layer: tool stickout and chip evacuation. A 6 mm tool with 25mm of stickout already deflects noticeably. That, not the travel figure, is the practical ceiling.
The One-Minute Summary
- Commercially available metric carbon sheet comes in only a few common thicknesses: 0.5 / 1 / 1.5 / 2 / 2.5 / 3 / 4 mm, so "can it cut 10mm?" is mostly a theoretical question for drone applications.
- Z-axis travel is not the bottleneck. After subtracting fixtures, spoilboard, and tool stickout, 80mm of travel still far exceeds any common sheet thickness.
- Reduce chip load once depth of cut exceeds 1×D: by 25% at 2×D and 50% at 3×D (Onsrud's recommendation).
- Nominal thickness is not actual thickness. A nominal 2mm carbon sheet may measure 1.78 ±0.20mm, so any fit based on sheet thickness must be measured.
- Thin sheet is hard because of Z-axis tolerance; thick sheet is hard because of tool rigidity. Both ends are difficult, and the 2–3mm middle is actually the easiest to cut.
First, What Thicknesses Can You Actually Buy?
Before talking about machining capability, let's pin down the need. The commercially available metric sizes of carbon fiber sheet for drones are actually quite concentrated:
| Thickness | Commercial availability | Typical drone parts | Machining challenge |
|---|---|---|---|
| 0.5 mm | Yes | Antenna spacers, insulating pads, lightweight dividers | Z-axis tolerance window is 60% of sheet thickness; automatic tool setting is a must |
| 1.0 mm | Yes | ESC covers, camera shrouds | Prone to chatter; needs vacuum or full-surface bonding |
| 1.5 mm | Yes | Camera mounts, small side plates | Workholding makes or breaks it |
| 2.0 mm | Yes | Top plates, middle plates, battery plates | Easiest range to machine |
| 2.5 mm | Yes | FPV bottom plates | Easiest range to machine |
| 3.0 mm | Yes | 7–10″ frame bottom plates, camera plates | Full depth in one pass with a 4 mm tool |
| 4.0 mm | Yes | 3–4″ arms, Armattan main plates | Multiple passes with 4 mm; one pass with 6 mm |
| 5.0 mm | Less common as a metric stock size | 5″ FPV arms (mainstream) | One full-depth pass with 6 mm (0.83×D) |
| 6.0 mm | Less common | 7–10″ arms | 1×D for a 6 mm tool, within the finishing range |
| 10 mm | Special order required | Large multirotor structural parts, laminated stacks | Multiple passes; tool stickout becomes the bottleneck |
| Standard metric thicknesses are based on BulkComposites' actual product listings (0.5 / 1 / 1.5 / 2 / 2.5 / 3 / 4 mm). 5mm and 6mm arms are mostly custom-made by frame makers or imperial sizes. Imperial suppliers (Rock West, DragonPlate) offer a wider thickness range, roughly 0.7mm to 6.35mm, with special items approaching 2 inches. | |||
Multiple Passes: Reduce Chip Load Beyond 1×D
Onsrud's composite cutting recommendations divide machining into three stages; the greater the depth of cut, the more the chip load per revolution must be reduced. As depth of cut increases, more fibers are engaged at once and there is less room for chip evacuation, so keeping the original chip load would push cutting force and heat buildup beyond what the tool can withstand.
Sheet thickness vs. number of passes
Recommended step-down strategy at different thicknesses for 4 mm and 6 mm tools
| Stage | Axial depth of cut | Chip-load adjustment | Depth with 4 mm tool | Depth with 6 mm tool | Edge quality |
|---|---|---|---|---|---|
| Finishing | 1 × D | Use recommended value | 4 mm | 6 mm | Best |
| Semi-finishing | 2 × D | Reduce 25% | 8 mm | 12 mm | Acceptable |
| Roughing | 3 × D | Reduce 50% | 12 mm | 18 mm | Leave finishing allowance |
| Note that this is the maximum depth per pass, not a statement that multiple passes are unnecessary. In practice, when cutting outside profiles, it is common to deliberately use two passes even when the depth is within range, to reduce exit-side delamination: the first pass leaves 0.3–0.5mm uncut, and the second pass cuts through. | |||||
Is the Z-Axis Travel Really Enough? Listing What Uses It
80mm or 100mm of Z-axis travel sounds far larger than 3mm sheet. But travel is not only for the sheet: tool length, workholding, the spoilboard, and retract clearance height all eat into it.
Cross-section: how Z-axis travel is used
Example: cutting 3mm CFRP with a 6 mm tool, actual allocation of the Carbon Lite's 80mm travel
The Real Limit: Tool Stickout
To cut through 10mm sheet, the tool needs at least 10mm of stickout plus a safety margin, about 15mm in practice. Tip deflection is proportional to the cube of stickout length and inversely proportional to the fourth power of shank diameter: δ ∝ L³ / d⁴.
| Sheet thickness | Recommended stickout | 4 mm relative deflection | 6 mm relative deflection | Recommendation |
|---|---|---|---|---|
| 1 mm | 6 mm | 0.06 | 0.01 | Both fine |
| 2 mm | 7 mm | 0.10 | 0.02 | Both fine |
| 3 mm | 8 mm | 0.15 | 0.03 | Both fine |
| 5 mm | 10 mm | 0.30 | 0.06 | 6 mm recommended |
| 6 mm | 11 mm | 0.39 | 0.08 | 6 mm recommended |
| 10 mm | 15 mm | 1.00 | 0.20 | 6 mm with reduced feed |
| 15 mm | 20 mm | 2.37 | 0.47 | 4 mm no longer suitable |
| 20 mm | 25 mm | 4.63 | 0.91 | Beyond a reasonable range for a desktop machine |
| Relative values derived from δ ∝ L³ / d⁴, not absolute deflection. Actual values also depend on tool material, clamping depth, and cutting parameters. For the full derivation, see ER11 collets and shank diameters. | ||||
The practical machining thickness limit for a desktop CNC in CFRP is about 10–15mm. It is set not by Z travel but by the largest tool diameter an ER11 collet can hold (6–7 mm) and the corresponding tool rigidity.
Common sheet thicknesses for drone parts are 0.5–6mm, all comfortably within range. Needs above 10mm are quite rare in drones and usually involve laminated structural parts on large multirotors.
Why Thin Sheet Is Actually Harder
Intuitively, thin sheet should be easier to cut, but in reality sheet under 1.5mm is noticeably harder than 3mm. There are three reasons, and none of them is about the tool:
| Challenge | Cause | Quantified | Solution |
|---|---|---|---|
| Narrow Z-axis tolerance window | The window between cut-through depth and acceptable spoilboard damage is fixed | 0.5mm sheet: window is 60% of thickness | Automatic tool setting + surfacing the spoilboard |
| Workpiece chatter | Thin sheet has low stiffness and vibrates under cutting force | — | Vacuum table or full-surface bonding to a spoilboard |
| Parts flying off after cut-through | Parts are so light that cutting force flings them away the instant they are cut free | — | Leave tabs or use vacuum hold-down |
| What the three challenges have in common: none of them is solved by adjusting parameters. Workholding and Z zeroing are what matter. See vacuum tables and fixturing in practice and automatic tool setting and Z zero. | |||
A Final Reminder: Nominal Thickness Is Not Actual Thickness
Few people notice this at the design stage. The actual thickness of carbon fiber sheet differs noticeably from its nominal value. Here are the published specifications of the material supplier Easy Composites for its double-sided carbon sheet:
| Nominal thickness | Actual thickness | Tolerance | Deviation from nominal |
|---|---|---|---|
| 0.25 mm | 0.22 mm | ±0.10 mm | −12% |
| 1.0 mm | 0.86 mm | ±0.15 mm | −14% |
| 2.0 mm | 1.78 mm | ±0.20 mm | −11% |
| 3.0 mm | 2.82 mm | ±0.25 mm | −6% |
| The direction and size of the deviation vary by supplier; this table reflects one manufacturer's published specifications only. Always go by the sheet you actually purchase. | |||
Any fit based on sheet thickness is affected: slot widths for tab-and-slot joints, the total height of stacked parts, mating faces that need to be flush, and screw lengths calculated from sheet thickness. If a nominal 2mm sheet is actually 1.78mm, stacking two of them is off by 0.44mm.
The right approach: measure the sheet with a micrometer as soon as you get it, then update your drawings accordingly. This also shows why in-house machining has an advantage during R&D: once you have measured the actual thickness, you can revise the drawing and recut the same day, whereas outsourcing means another full round.
FAQ
Does 100mm of Z-axis travel mean I can cut 100mm-thick material?
No. Z travel is the total distance the spindle can move vertically, and that distance has to be shared among fixture height, spoilboard thickness, tool stickout, workpiece thickness, and retract clearance height. When cutting 3mm sheet, for example, about 45mm is actually used. What really limits machining thickness is tool stickout and rigidity; on a desktop machine, the practical limit in CFRP is about 10–15mm.
How many passes does a 6mm arm need?
With a 6 mm tool, 6mm is exactly 1×D, which falls in the finishing range Onsrud defines, so in theory it can be cut full depth in one pass. In practice, though, we recommend two passes: cut 5.5mm on the first pass without breaking through, then cut through on the second. This noticeably reduces exit-side delamination. With a 4 mm tool, two passes (3mm each) are required.
Why are 5mm and 6mm metric carbon sheets hard to find?
Standard metric sheet supply is concentrated at 0.5–4mm. 5mm and 6mm are more common as imperial sizes (3/16″ = 4.76mm, 1/4″ = 6.35mm) or as custom orders from frame makers. If you want to make your own 5″ FPV arms, the usual practical approach is to buy 6.35mm imperial sheet, or order directly from a supplier that specializes in carbon sheet for drones.
Thin parts tend to fly off once they're cut free. Are there options besides leaving tabs?
There are three: vacuum table hold-down (the most thorough, but holding force drops sharply on small parts with little surface area), thin high-strength double-sided tape bonding the sheet to a spoilboard (avoid foam-backed tape, which springs), and onion skin (leave 0.1–0.2mm uncut and separate the parts by hand at the end). However, practitioners report that without vacuum hold-down, onion skin has a low success rate, because the sheet shifts and the tool cuts straight through and flings the part.
Is carbon sheet over 10mm really impossible to cut?
It can be cut, but you have to accept two things: first, you must use a 6 mm tool and reduce the feed, so machining time grows noticeably; second, edge quality drops, because with 15mm or more of tool stickout, deflection is already at 1.0x or more of the 4 mm baseline. If you need this often, the more sensible approach is to move to a larger machine, or split the thick part into thinner sheets and bond them as a laminated stack.
Sources
- Onsrud, Composite Cutting Data Recommendations (depth-of-cut stages 1×D / 2×D / 3×D and chip-load adjustments of −25% / −50%), accessed September 3, 2026 — https://onsrud.com/images/Composite.pdf
- BulkComposites, 3K Twill/Plain Matte Carbon Fiber Sheets & Plates (metric thicknesses 0.5 / 1 / 1.5 / 2 / 2.5 / 3 / 4 mm), accessed September 3, 2026 — https://www.bulkcomposites.com/3k-twill-matte-carbon-fiber-sheets-plate/
- Rock West Composites, Carbon Fiber Plates (imperial thicknesses from about 0.03″ to 0.25″, special items approaching 2 inches), accessed September 3, 2026 — https://www.rockwestcomposites.com/carbon-fiber-plates
- Easy Composites, Double Sided High Strength Carbon Fibre Sheet (nominal vs. actual thickness table), accessed September 3, 2026 — https://www.easycomposites.eu/double-sided-high-strength-carbon-fibre-sheet
- Oscar Liang, FPV Drone Frames (5″ arms mostly 5mm, 6mm for advanced builds; top, middle, and bottom plates 2–3mm), accessed September 3, 2026 — https://oscarliang.com/fpv-drone-frames/
- iFlight official frame specification pages (Chimera7/9 and CX10: 6mm arms, 3mm bottom plate, 2mm top plate), accessed September 3, 2026 — https://shop.iflight.com/Chimera7-ECO-Frame-kit-Pro2079
- Carbon-CNC Carbon Pro / Carbon Lite machine specifications (Z-axis travel 100 / 80mm, ER11 collet, 4/6mm shanks) — https://www.carbon-cnc.com/en/carbon-pro/
0.5mm to 6mm, All Comfortably Within Range
Carbon-CNC machines offer 100mm (Pro) / 80mm (Lite) of Z-axis travel, with an ER11 collet and 4mm and 6mm shank end mills, covering every common sheet thickness for drone parts. To find out which model suits your sheet thicknesses and part sizes, contact us.
Get a Quote