What actually drives the price of an acrylic part

A customer often assumes the price is the material plus a margin. On a simple flat part the sheet is the largest single item. On anything machined, polished or bonded, labour dominates, and the design decisions that create labour are usually invisible to the person who drew them.

The seven levers, in order of impact

1. Edge polish. Diamond polishing is hand work priced per metre. On a small thick part it can exceed the material cost entirely.
2. Tolerance. A general tolerance is free. A quoted ±0.1 mm on a 900 mm part means slower feeds, more measurement and possible rejection — a different process, not a tighter setting.
3. Machining time. Every pocket, hole pattern and profile adds path length. A part with 40 holes costs considerably more than the same outline with 4.
4. Finishing and assembly. Bonding, annealing, printing and clear coating are separate operations with their own handling.
5. Material grade. Cast over extruded, ESD, flame-retardant or optical grades each add a multiple, and unusual thicknesses add lead time as well as cost.
6. Quantity. Setup cost is spread across the batch, so the second 50 parts are much cheaper than the first.
7. Inspection. First-article reports and 100% dimensional checks add days and cost, and are only worth specifying where the part is critical.

Where the money actually goes

Typical cost structure for three kinds of acrylic part

Part type	Dominant cost	Small change with big effect
Flat cut panel, no polish	Material	Reduce thickness by one step; nest parts to reduce waste
Display piece, polished	Edge polish labour	Polish only the visible edges; design so fewer edges show
Machined enclosure, bonded	Machining + bonding labour	Fewer holes; one fillet instead of a complex rebate; avoid annealing if not needed
Printed front panel	Print setup + material	Reverse print in one pass instead of surface print plus clear coat
Low-volume prototype	Setup, not production	Accept a general tolerance and a routed edge

Design decisions that reduce cost without looking cheaper

• Hide edges instead of polishing them. A shadow gap, a frame or an overlap costs less than a metre of diamond polish and often looks better.
• Use one thickness. A part set that uses 5 mm throughout avoids a second sheet and a second setup.
• Round corners to a stock cutter radius. A custom radius needs a custom cutter or a slower path.
• Avoid holes in visible faces. Each hole in a polished face needs re-polishing afterwards.
• Standardise the fixing. One hole size and one washer across a product range reduces error and inspection.
• Let the fabricator choose the edge finish on hidden edges, and state only what is seen.

What tightening the tolerance really buys

Customers often ask for ±0.1 mm because it sounds precise. Whether it is worth paying for depends on what the part mates with.

Tolerance against what it costs and what it achieves

Tolerance	Process implication	Worth it when
±0.5 mm general	Normal routing, normal feed	Almost everything — panels, displays, covers
±0.2 mm	Slower feed, more measurement	Holes that take a pin, mating parts, printed registration
±0.1 mm	Controlled feed, temperature awareness, inspection	Precision parts under 300 mm, optical mounts
±0.05 mm	Special process, selected sheet, measurement uncertainty matters	Rarely appropriate for acrylic at all

A ±0.1 mm callout on a 1,500 mm acrylic panel is not achievable in any meaningful sense: the sheet itself expands more than that over a few degrees of temperature change. The tolerance should match the size as well as the function.

Quantity effects that surprise people

The first part carries the setup, the programming, the sheet purchase and the sample approval. Ten parts spread that over ten. A hundred parts make the per-unit production cost visible, and that is where the real unit price is.

The exception is a part with a lot of hand finishing. Polishing and bonding labour scales linearly with quantity, so a hundred polished blocks do not get much cheaper per unit than ten. When a customer asks for a volume price on a polished part and is disappointed, this is usually why.

What to send for an accurate price

1. A drawing or a DXF with dimensions and hole positions.
2. Material and thickness, and whether cast or extruded is acceptable.
3. Which edges and faces are visible, and to what standard.
4. The tolerance for anything that mates with another part.
5. Quantity, and whether a sample is needed first.
6. The date the parts are needed on site, not the date the order is placed.

With those six, a quote is accurate. Without the third and sixth, it is a guess — and the guess is always the one that changes later.

Questions this article answers

Related reading

• How tight should the tolerance be?
• Edge finishes and their cost
• FAQ: pricing questions
• Request a quote
• MOQ and setup cost
• Planning the lead time