General Tolerances Guidance
If a CAD model only is supplied with the job, then the application-specific tolerances listed below apply. However, if a blueprint is provided, all tolerances of the print supersede the CAD model tolerancing.
If only a CAD model is supplied the following tolerances apply to machined surfaces:
- For features of size (Length, width, height, diameter) and location (position, concentricity, symmetry) +/- 0.005”
- For features of orientation (parallelism and perpendicularity) and form (cylindrical, flatness, circularity, and straightness) apply tolerances as shown in the table below.
If a blueprint is provided, all tolerances of the print supersede the CAD model tolerancing above. Any supporting dimensioning on blueprints such as GD&T callouts, tap sizes, inserts, specific surface roughness must be followed. Parts that do not require plating or surface treatment must be supplied “as machined” and at most be polished with scotch brite unless there are requirements for sandblasting, bead blast, shot peen, tumble, etc. The surface roughness requirement for “as machined” surfaces is Ra 125 micro-inches maximum. If no Class of Threads is called out on the drawing, Class 2 is assumed.
Flat Sheet Metal Parts
Sheet metal parts that utilize stock material gauge thicknesses and require no bending or milled features. All flat sheet metal parts can meet a +/-0.005” (+/- 0.127mm).
Simple Sheet Metal Bend / One Surface
When designing parts with some type of bend with a standard bend radius, sheet metal tolerances are required to open. For simple bent parts, Xometry can offer a +/- 0.010” (+/- 0.254mm) tolerance for dimensions across a single bend. The bend radius itself is constrained to a +/- 1.0°
Multiple Sheet Metal Surface Bends
For dimensions measured over multiple bends, Xometry can offer a +/- 0.030 (0.762mm).
Additive Tolerances & Standards
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Injection Molding Standards
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