5-axis machining
Compound angles · single setup
CNC Acrylic Machining — 3-Axis & 5-Axis
Milling, drilling and routing PMMA sheet and block on 8× 3-axis and 1× 5-axis centers — annealed, polished-ready, prototype to production.
Reply within 12 hours · free DFM feedback
5-axis CNC machining a complex clear acrylic part
CNC acrylic machining is the milling, drilling and routing of PMMA sheet or block on computer-controlled machining centers. Done correctly — sharp single-flute tooling, high spindle speeds, controlled feeds and post-machining annealing — it holds tolerances of ±0.05 mm and leaves edges clear enough to polish to full transparency.
Equipment & capacity
Eight 3-axis machines mean parallel production — large orders don’t queue behind one spindle. The 5-axis center handles compound angles and side features without refixturing, where most acrylic shops subcontract out. We don’t.
| 3-axis CNC machining centers | 8 · working envelope up to 3000 × 2000 mm |
| 5-axis CNC machining center | 1 · 1200 × 1000 × 500 mm · angled features & complex geometry in one setup |
Milled clear part
Sharp tooling · polished-ready edge
Machined detail
±0.05 mm · annealed
Machining specs
| Tolerance | ±0.1 mm standard, ±0.05 mm critical |
| Thickness | 3–100 mm |
| Min feature | Ø1 mm holes, 1 mm slots |
| Surface finish | Machined, then flame / diamond polished per drawing |
| Threads | Tapped holes ≥ M3; brass inserts for repeated assembly |
| Files accepted | STEP, IGES, DWG, DXF, PDF |
Why acrylic machining is its own skill
Acrylic is unforgiving: wrong feeds melt the cut, dull tools leave stress that crazes later, aggressive clamping cracks corners. Our process rules — developed since 2014 for clear engineering plastics:
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Right tooling
Single-flute polished carbide, swapped on schedule not on failure.
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Feeds tuned to cut
Speeds set per thickness to cut, not melt the edge.
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DFM on corners
Corner radii ≥ tool radius designed in — sharp internal corners crack.
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Annealed as standard
Eliminates crazing when parts later meet solvents or load.
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First-article inspection
On every new drawing, before production releases.
FAQ
What tolerance is realistic for machined acrylic?
±0.1 mm routinely, ±0.05 mm on critical dims. Tighter is possible but usually wasted — acrylic’s thermal expansion (~0.07 mm/m/°C) exceeds micron tolerances across normal temperature swings.
Do you machine other plastics?
Acrylic (PMMA) is our specialty. We machine Acrylic (PMMA) and polycarbonate (PC) only; we do not fabricate PVC, PETG or HDPE.
How fast can I get a machined prototype?
48 hours from approved drawing for typical parts, plus shipping.
Why do machined acrylic parts sometimes crack weeks later?
Residual machining stress plus solvent exposure causes crazing. Annealing prevents it — which is why it’s standard in our process, not an upcharge.
Which drawing formats do you accept?
STEP, IGES, DWG, DXF and PDF, or a dimensioned sketch and photos of the part; if there is no CAD file, our engineers draft a manufacturing drawing for your approval.
How do you handle drawing revisions?
Each drawing is held under your part number with version control, and a revision change triggers a new first-article inspection so production always matches the approved revision.
Why do machined acrylic parts sometimes craze or crack later?
Residual machining stress plus solvent, fastener or load exposure causes crazing; annealing with the cast-acrylic industry-standard schedule reduces that risk, which is why it is standard in our process, but it does not guarantee the part against every service condition.
What happens before production releases?
Every new drawing gets a first-article inspection of the critical features, and reorders run on the same CNC programs with the material grade locked to the part number.
Can a factory machine an assemblable acrylic part straight from my drawing?
Yes, with a review first. STEP, IGES, DWG, DXF and PDF drawings are accepted, or a dimensioned sketch with sample-part photos; engineers can produce a manufacturing drawing from a sketch when no CAD file exists. Every new drawing passes a manufacturability review before quoting: material, datums, hole positions, mating faces, radii and critical dimensions.
How are critical dimensions on machined acrylic parts verified?
Drawing-called critical dimensions are confirmed on the 5-axis center at ±0.05 mm against the drawing plus first-article inspection; general tolerances follow GB/T 1804-2000 / ISO 2768 and vary with size span, and holes and machined features are quoted at ±0.1 mm. Inspection uses calibrated measuring tools, and the method for critical features is confirmed per order.
What stops machined acrylic from developing stress cracks later?
Machined parts are annealed with the cast-acrylic industry-standard schedule to reduce residual stress; specific temperature and soak values are confirmed per grade, not published. Annealing reduces but does not eliminate cracking risk, so aggressive solvents, sustained load, fasteners or thermal cycling need a design and process review before quoting.
Get a machining quote
Send your CAD file for free DFM feedback within 12 hours.
Evidence and verification
- First-article reports, dimensional reports and material certificates are supplied on request per order.
- A certificate of conformity or batch COA can be supplied per order on request.
- Tolerance, process and annealing statements on this page are company-declared by AcrylicFabWorks unless stated otherwise.
- Applicable product grade: Cast and extruded acrylic (PMMA) sheet and block
- Fact owner: Engineering and quality review, AcrylicFabWorks
- Last reviewed: 2026-08-27
Technical details
Factory & quality system
CNC router cutting a large clear acrylic sheet on a flatbed
CNC router cutting a large clear acrylic sheet on a flatbed
Close-up of a precision machined clear acrylic component
Close-up of a precision machined clear acrylic component
Technical details
Ordering & lead times
Drawing formats we accept
Company-declared
Drawing review before quoting
Every new drawing passes a drawing review for manufacturability before quoting: material and thickness, datum features, hole positions, mating faces, corner radii, wall sections and which dimensions are critical are confirmed and listed on the quote.
Technical details
Choosing the right route
Process rules for clean machining
Sharp single-flute tooling replaced on schedule, feeds tuned per thickness, DFM corner radii and first-article inspection on every new drawing are the process rules that keep machined features clean and repeatable.
Version control and revisions
Drawings are held under your part number with version control; a revision change triggers a new first-article inspection so production always matches the approved revision.
Tolerance bands we hold
General tolerances follow GB/T 1804-2000 / ISO 2768 and vary with the size span; holes and machined features are quoted at +/-0.1 mm, and drawing-called critical dimensions on the 5-axis center are confirmed at +/-0.05 mm against the drawing plus first-article inspection.
Annealing and crazing risk
Machined parts are annealed as standard with the cast-acrylic industry-standard schedule to reduce residual stress before bonding or final finishing; annealing reduces but does not eliminate the risk of crazing or cracking.
Tolerance class selection for your features
| Choose this when | Do not choose this when | Tolerance | Claim IDs |
|---|---|---|---|
| The feature is a hole, slot or machined feature with no tighter call-out | The feature is a mating face or critical dimension with a drawing call-out | General tolerance per GB/T 1804-2000 / ISO 2768 by size span; +/-0.1 mm typical on holes and machined features | AF-C03, AF-C01 |
| Your drawing calls out a critical dimension that controls assembly fit | The dimension is a standard feature already covered by general tolerance | Critical dimension at +/-0.05 mm on the 5-axis center, confirmed per drawing plus first-article | AF-C02 |
| The part exceeds the confirmed scope for a tolerance class | The part fits within confirmed size and thickness ranges | Tolerance agreed per drawing and first-article; no blanket full-part band |
Is your drawing ready for machining review?
| Choose this when | Do not choose this when | Readiness | Claim IDs |
|---|---|---|---|
| You have a CAD model or dimensioned drawing | You only have a vague concept without dimensions | Send STEP, IGES, DWG, DXF or PDF for review | AF-C14 |
| You have a sketch or sample part only | The geometry must be exact and no sketch is possible | We draft a manufacturing drawing for your approval | |
| The part will be bonded, threaded or fitted to other components | The part is standalone with no assembly interfaces | Confirm mating faces and datums in the drawing |
Tolerance applicability conditions (all company-declared; per-part confirmation required)
| Property | Value | Unit | Product grade | Thickness specimen | Test method / standard | Evidence status | Qualification | Claim IDs |
|---|---|---|---|---|---|---|---|---|
| General tolerances | GB/T 1804-2000 / ISO 2768, class varies with size span | n/a | Cast and extruded acrylic | 3-100 mm | GB/T 1804-2000; ISO 2768 | company-declared | Grade and size-span mapping pending | AF-C03 |
| Machined feature tolerance | +/-0.1 mm on holes and machined features | mm | Machined acrylic | 3-100 mm | Dimensional inspection per drawing | company-declared | Applicable hole diameter and thickness range pending | AF-C01 |
| Critical dimension tolerance | +/-0.05 mm on drawing-called critical dimensions via the 5-axis center | mm | Machined acrylic | Order-specified | Drawing call-out plus first-article inspection | company-declared | Critical-feature definition and size cap pending; never a full-part band | AF-C02 |
| Fabrication thickness range | 3-100 mm | mm | Cast and extruded acrylic | Sheet and block | Company statement | company-declared | Cast versus extruded ranges pending | AF-C05 |
| Minimum machined feature | 1 mm holes and slots | mm | Machined acrylic | Order-specified | Per drawing and tooling | selection guidance | Confirmed per geometry and thickness | |
| Threads | Tapped holes from M3; brass inserts for repeated assembly | n/a | Machined acrylic | Order-specified | Per drawing | selection guidance | Thread engagement confirmed per thickness |
Annealing and stress-control conditions
| Property | Value | Unit | Product grade | Thickness specimen | Test method / standard | Evidence status | Qualification | Claim IDs |
|---|---|---|---|---|---|---|---|---|
| Annealing schedule | Cast-acrylic industry-standard schedule applied to machined parts | n/a | Cast acrylic | Order-specified | Company process statement | company-declared | Specific temperature and soak parameters not published | AF-C10 |
| Annealing outcome | Reduces residual stress and crazing risk | n/a | Machined acrylic | Order-specified | Company process statement | company-declared | Does not eliminate cracking risk; service conditions still matter | AF-C10 |
| Solvent and bonding exposure | Annealed parts are preferred for solvent bonding; flame-polished edges are annealed before bonding | n/a | Machined acrylic | Order-specified | Company process guidance | selection guidance | Confirmed per application | |
| Fastener and load conditions | Residual stress plus sustained load or aggressive solvents can still cause crazing | n/a | Machined acrylic | Order-specified | Company process guidance | selection guidance | Design review per application |
Frequently asked questions
Q: What tolerance can you hold on machined acrylic parts? A: Our 3-axis and 5-axis CNC centers machine PMMA to tolerances of ±0.1 mm on typical features, with tighter control on critical dimensions called out on your drawing.
Q: Do you offer 5-axis CNC machining for acrylic? A: Yes. We run a 5-axis CNC machining center alongside eight 3-axis centers, which lets us machine complex contoured and multi-face PMMA parts in a single setup.
Q: Cast or extruded acrylic for CNC machining? A: Cast acrylic machines cleaner with lower internal stress and less chipping, so it is preferred for precision machined parts; extruded acrylic is used where thickness consistency and cost matter more than tight tolerance.