Acrylic Sheet Fabrication and Machining for OEM Applications
The optically clearest engineering thermoplastic on the market — 92% light transmission, harder and more scratch-resistant than polycarbonate, and the only plastic that polishes to a finished, glass-like edge. Cast acrylic by default, fabricated to your drawings in Riverview, Michigan.
What Is Acrylic?
Acrylic is a rigid, transparent thermoplastic. Its chemical name is polymethyl methacrylate — PMMA — and you'll see it sold under brand names you'll recognize: Plexiglas®, Lucite®, Acrylite®, Optix®, and Perspex®. The terms "acrylic," "plexiglass," and "PMMA" all refer to the same base material.
What sets acrylic apart from other transparent plastics: it transmits 92% of visible light (slightly more than glass), it resists yellowing under sustained UV exposure, and it polishes to a finished optical edge that no other engineering plastic can match cleanly. The trade-off is brittleness — acrylic is harder than polycarbonate but cracks under sharp impact where polycarbonate would flex.
At Wm. F. McGraw & Co., we fabricate acrylic sheet to your drawings — cut, CNC-machined, drilled, routed, and polished — for production runs from one prototype to repeat orders. Choose acrylic when the optics matter; choose polycarbonate when impact matters.
OEM Buyer's Note
"Most acrylic problems come from machining the wrong sheet — extruded stock used for parts that needed cast. We work in cast acrylic for fabrication jobs by default."
— Why cast vs extruded matters more than the brand on the sheet
Acrylic Properties
Typical values for clear, general-purpose cast acrylic. Values vary by grade and manufacturer — consult the specific datasheet for your application.
| Property | Typical Value | Why It Matters |
|---|---|---|
| Tensile strength | 9,500–11,500 psi | Strong enough for rigid structural panels and lenses |
| Impact strength (notched Izod) | 0.3–0.5 ft-lb/in | Lower than polycarbonate — design around it for impact-prone parts |
| Continuous service temperature | Up to ~180°F | Suitable for indoor and protected-environment service |
| Heat deflection temperature | 190–210°F at 264 psi | Holds shape under moderate heat and load |
| Light transmission (clear) | 92% | Highest of any common transparent plastic — beats glass slightly |
| Refractive index | 1.49 | Optical-grade clarity for lenses and displays |
| UV resistance (uncoated) | Excellent | Resists yellowing in long-term sun exposure |
| Hardness (Rockwell M) | 85–105 | Significantly harder than polycarbonate — better scratch resistance |
| Water absorption (24 hr) | 0.2% | Stable in normal humidity |
| Density | 1.18 g/cm³ | About half the weight of glass at equivalent dimensions |
+ Key Strengths
- Highest optical clarity of any common transparent plastic — 92% light transmission
- Excellent UV resistance — resists yellowing in long-term outdoor service
- Harder and more scratch-resistant than polycarbonate (uncoated)
- Polishes to a finished, glass-like edge using flame, diamond, or solvent polishing
- Lightweight — about half the weight of glass
- Wide grade range — clear, tinted, mirrored, anti-microbial, light-diffusing, impact-modified
- Lower cost than polycarbonate at equivalent thicknesses
! Limitations to Design Around
- Brittle — low impact resistance compared to polycarbonate
- Service temperature limited to ~180°F continuous
- Notch-sensitive — sharp internal corners concentrate stress and crack
- Vulnerable to certain solvents (acetone, MEK, alcohols)
- Extruded grades have residual stress that complicates machining — cast is preferred
Cast vs Extruded Acrylic
Acrylic sheet is manufactured two ways. Most engineers don't think about it until they get a part back with crazing, cracks, or stress lines — at which point the difference matters a lot. Here's the short version.
Cast Acrylic
Process: Liquid monomer is poured between glass plates and slowly cured.
The result is sheet with uniform molecular structure, minimal residual stress, and excellent machining behavior. Cast is the right choice for any part that will be machined, drilled, polished, or thermoformed.
- Machinability: Excellent — clean chips, low stress
- Polishability: Flame, diamond, solvent — all work cleanly
- Thickness: Thin sheet through 4″+ block
- Best for: Machined parts, polished edges, prototyping
Extruded Acrylic
Process: Pellets are melted and pushed through a die.
Faster and cheaper to make, but the sheet has anisotropic stress (different properties along X and Y axes) and softer surfaces. Fine for cut-to-size sheet that won't see further machining; not the right choice for parts that will be machined or polished.
- Machinability: Poor — gummy, prone to chipping
- Polishability: Mediocre — surface defects more common
- Thickness: Generally thinner gauges only
- Best for: Cut-to-size sheet, no further fabrication
| Property | Cast Acrylic | Extruded Acrylic |
|---|---|---|
| Manufacturing process | Monomer poured between glass plates, cured | Melted pellets pushed through a die |
| Machinability | Excellent — clean chips, low internal stress | Poor — gummy, prone to chipping and crazing |
| Optical clarity | Highest — uniform across the sheet | Slightly less uniform; minor distortion possible |
| Thickness range | Thin sheet through 4″+ block | Generally thinner gauges only |
| Stress distribution | Uniform — minimal residual stress | Anisotropic — stress in extrusion direction |
| Polishability | Excellent — flame, diamond, solvent all work | Mediocre — surface defects more common |
| Cost | Higher | Lower |
| Best for | Machined parts, polished edges, prototyping | Cut-to-size sheet, no further machining |
Our Default
For machined parts, polished edges, and any fabrication beyond a simple cut, we work in cast acrylic. Extruded is available when the application is right for it, but cast is the safer engineering choice for almost every job that comes through our shop.
Acrylic Grades We Fabricate
Acrylic is a family of grades, each engineered for a specific use case. We fabricate all of the major commercial grades.
General-Purpose Clear Acrylic
The standard grade — used for displays, lenses, viewing windows, signage, and any application where transparency and dimensional stability are the primary requirements.
Anti-Microbial Acrylic
Embedded with antimicrobial agents that resist bacterial growth on the sheet surface — used in medical equipment, food-processing covers, and clean-environment applications.
Abrasion-Resistant Acrylic
Surface-coated to resist scratching from regular contact, cleaning, or environmental abrasion. Used for machine guards, viewing windows, and any sheet that sees sustained use.
Impact-Modified Acrylic
Engineered with elastomeric modifiers that improve impact resistance closer to polycarbonate territory. Used where you need acrylic's optical clarity and UV stability but the part can't be brittle.
UV-Filtering Acrylic
Blocks UV transmission to protect contents inside an enclosure — used for museum cases, retail displays, and pharmaceutical equipment where UV degradation of the contents is the concern.
Mirrored Acrylic
Acrylic with a metallic backing — lighter and more shatter-resistant than glass mirrors. Used for instrument panels, retail fixtures, and specialty equipment.
Light-Diffusing Acrylic
White or translucent grades engineered to diffuse light evenly across the sheet — the standard material for backlit signs, lighting fixtures, and edge-lit displays.
Anti-Static Acrylic
Surface-treated to dissipate static charge — used in clean rooms, electronics manufacturing, and any environment where static buildup is a concern.
Tinted & Colored Acrylic
Solid colors, transparent tints, and specialty finishes for aesthetic, branding, and light-control applications.
Our Acrylic Fabrication Capabilities
We fabricate acrylic in-house at our Riverview, Michigan facility. Every job is run on equipment configured for plastics, with tooling and feeds matched to the grade.
- CNC machining — milling, drilling, tapping, and 3-axis profiling to drawing
- CNC routing — for complex 2D shapes and edge profiles
- Precision cutting — saw, laser (where appropriate), and waterjet cutting
- Drilling & counterboring — sharp tooling and slow feeds to prevent crazing
- Edge polishing — flame, diamond, solvent, and buff polishing for finished optical edges
- Annealing — controlled stress relief to prevent post-machining cracking
- Cut-to-size — sheet stock cut to your dimensions
- Custom prototypes through repeat production
On Acrylic Machining
Acrylic chips, cracks, and crazes when machined wrong. Sharp tooling, light passes, controlled feeds, proper coolant, and post-machining stress relief are the difference between a production-ready part and a scrap pile. We run cast material by default for any job that requires more than a clean cut.
Acrylic Polishing Methods
Acrylic is the only engineering plastic that polishes to a true glass-like edge. The right method depends on the part and the finish you need — we run all four in-house.
Flame Polishing
A fine flame is passed over the cut edge to melt the surface back to clarity.
Best for: Straight edges, fast turnaround. Not ideal for thick stock or complex profiles where heat distortion is a risk.
Diamond Polishing
A diamond-tipped tool runs along the edge at high speed, producing a finished optical surface in one pass.
Best for: Medical, optical, and display applications where the edge is part of the finished product.
Buff Polishing
Compound and a polishing wheel work the edge to a smooth, high-gloss finish.
Best for: Parts where a high-gloss but not optically perfect finish is acceptable.
Solvent Polishing
Chemical polishing dissolves the surface back to clarity for shapes mechanical tooling can't reach.
Best for: Complex shapes where mechanical polishing would be impractical.
Common Acrylic Applications
Acrylic is used wherever optical clarity, finished edges, or UV stability matter. These are the applications we fabricate most often.
Medical Equipment Covers & Housings
Anti-microbial grades for clinical environments
Lighting Components
Diffuser panels, lens covers, edge-lit displays
Transit Glazing
Buses, light rail, and specialty vehicles where UV stability matters
Instrument & Gauge Panels
Clear and tinted grades for control equipment covers
Display Cases & Cabinets
Retail fixtures, museum cases, and equipment displays
Viewing Windows
For laboratory and process equipment
Lenses & Optical Components
Clear and tinted grades for non-critical optics
Signage & Architectural Panels
Interior and protected exterior use
Clean Room Components
Anti-static grades for electronics and pharma facilities
Skylights & Structural Glazing
Where weight reduction matters
Acrylic vs Polycarbonate: How to Choose
Acrylic and polycarbonate are often considered interchangeable. They aren't. The wrong material in the wrong application gets you a brittle break or a scratched surface that should never have been there.
| Property | Acrylic (PMMA) | Polycarbonate |
|---|---|---|
| Optical clarity | 92% transmission — clearest | 88–90% |
| Impact strength | Low — brittle | Highest — ~250× glass |
| UV resistance (uncoated) | Excellent | Moderate — coating recommended |
| Scratch resistance (uncoated) | Higher | Lower — coating recommended |
| Service temperature | Up to ~180°F | Up to ~240°F |
| Polishability | Excellent — flame, diamond polish | Good but harder to achieve clear-edge finish |
| Cost | Lower | Higher |
| Best when | Optics, polished edges, UV exposure | Impact and toughness matter most |
PMMA Choose Acrylic when…
- Optical clarity is the primary requirement (lenses, displays, viewing covers)
- The part needs polished, finished edges
- Long-term outdoor UV exposure is a primary concern
- Scratch resistance matters more than impact resistance
- Cost is a factor and impact strength isn't critical
PC Choose Polycarbonate when…
- Impact resistance is the primary requirement (machine guards, safety shields)
- Operating temperature exceeds ~180°F
- UL flame ratings are required
- FDA compliance is needed for medical or food-contact applications
Need help deciding? See our Polycarbonate Fabrication page → or send us your application — we'll recommend the right material before we quote.
Industries We Serve with Acrylic
From anti-microbial medical covers to instrument panels and viewing windows, our acrylic fabrication shows up across the OEM spectrum.
Aerospace
Instrument covers, viewing windows, interior panels
Medical
Anti-microbial covers, equipment housings, sterilizable display panels
Electric Vehicles
Interior trim, instrument covers, display lenses
Power Electronics
Clear control covers and indicator lenses
Switchgear
Viewing windows for cabinet inspection (where flame rating allows)
Motor Applications
Gauge covers, indicator housings, viewing ports
Why OEMs Choose Us for Acrylic
Cast acrylic by default, every grade in stock, every polishing method in-house — under one roof in Riverview, Michigan.
Cast acrylic by default for fabrication
Most acrylic problems come from machining the wrong sheet — extruded stock used for parts that needed cast. We work in cast acrylic for fabrication jobs by default. You don't have to specify it; we already know.
Full polishing capability in-house
Flame, diamond, solvent, and buff polishing all under one roof. If your part needs a finished optical edge, we deliver it without sending the work out.
Engineered fabrication, not online instant quotes
Acrylic crazing, stress cracking, and notch sensitivity aren't theoretical — they show up in the part you receive. We've been fabricating acrylic for OEMs for decades. Protocols are dialed in.
All grades, in one place
Clear, anti-microbial, abrasion-resistant, impact-modified, UV-filtering, mirrored, light-diffusing, anti-static, tinted — we fabricate the full grade range. You specify what your application needs, not what's on our shelf.
Prototype through production
One-off prototype, low-volume run, or recurring production — we support all three. Many of our OEM customers start with a prototype and scale into ongoing supply.
Quotes in 1–2 business days
Send a drawing or describe the application. Most quotes turn around in one to two business days — with the right grade and the right fabrication approach already specified.
Frequently Asked Questions
Quick answers about cast vs extruded, grades, polishing, and how to get a quote.
What's the difference between cast and extruded acrylic?
How does acrylic compare to polycarbonate?
Is acrylic the same as Plexiglas or PMMA?
What's the temperature range for acrylic?
Can you polish acrylic to a finished optical edge?
Do you fabricate anti-microbial or medical-grade acrylic?
Do you machine to drawings or only cut to size?
How do I get a quote?
Request an Acrylic Quote
Tell us what you're building. We'll come back with the right grade — cast or extruded, clear or specialty — and the right fabrication approach for your application.
