Mechanical finishing & post-processing · finish comparison
As Machined vs Surface Grinding
As Machined and Surface Grinding are both mechanical finishing finishes; as machined is the lower-cost option ($).
As Machined
Mechanical finishing · $
As machined is the baseline CNC condition with no secondary cosmetic finishing.
Surface Grinding
Mechanical finishing · $$$ · instant quote
Surface grinding uses a bonded abrasive wheel to generate precise flat surfaces.
When to choose which
Choose As machined
As machined is the pick when its strengths below matter more than Ground's.
- Lowest secondary-process cost
- Common Ra 1.6–3.2 µm (63–125 µin)
- Best preservation of machined dimensions
Choose Ground
Choose Ground when tighter flatness and lower Ra are required.
- Can hold about ±0.005 mm on suitable work
- Produces Ra about 0.2–1.6 µm (8–63 µin)
- Creates flat parallel mating faces
What the numbers say
- As machined is the lower-cost option ($).
Scores side by side
Each score is 0–100 against every finish in this catalog. Corrosion is derived from salt-spray test duration and surface hardness from the finish layer's Vickers hardness where a measured figure exists; a finish that leaves the base metal's own surface is not rated for hardness. Cosmetic, lubricity and cost are FabDigit's engineering assessment. Scores and typical figures are screening data, not matched side-by-side tests or service-life rankings; ASTM B117 is a controlled salt-fog method, not a field-life prediction.
| Score | As machined | Ground |
|---|---|---|
| Corrosion resistance | 0 Minimal | 0 Minimal |
| Surface hardness / wear | — — | — — |
| Cosmetic quality | 20 Low | 35 Fair |
| Lubricity | 10 Minimal | 20 Low |
| Cost | 0 $ | 45 $$$ |
Key numbers
| Property | As machined | Ground |
|---|---|---|
| Thickness | 0 µm | 0 µm |
| Electrical | Unchanged | Unchanged |
| Relative cost | Budget ($) | Premium ($$$) |
| Added lead time | 0 working days | 2–7 working days |
| RoHS | Compliant | Compliant |
| Instant quote | On request | Yes |
Bold marks the side that is ahead on a row where more (or less, for cost and lead time) is better. Ranges are the typical specification window; the drawing call-out fixes the class.
Which materials take each finish
| Material family | As machined | Ground |
|---|---|---|
| Aluminum | Yes | With care |
| Brass | Yes | With care |
| Copper Alloy | Yes | With care |
| Polymer | Yes | No |
| Stainless Steel | Yes | Yes |
| Steel | Yes | Yes |
| Titanium | Yes | With care |
| Ceramic | — | With care |
| Magnesium Alloy | With care | With care |
| Zinc Alloy | With care | With care |
As machined vs Ground — frequently asked
What is the difference between As machined and Ground?
As Machined and Surface Grinding are both mechanical finishing finishes; as machined is the lower-cost option ($).
When should I use As machined instead of Ground?
Conversely: choose Ground when tighter flatness and lower Ra are required.
Is As machined or Ground cheaper?
As machined is the lower-cost finish ($ against $$$ for Ground) among the finishes FabDigit quotes. Both are priced per part with a lot minimum; the exact figure appears on the instant quote once the part is uploaded.