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Auto Specs

You can specify various general technical information about your part at menu Job | Settings | Specifications: Auto. These settings are described here.

Recommended Settings

Recommended settings for all items below are available by clicking one of the buttons at the bottom of the dialog. However it is best to select your own values depending on your specific requirements.   

General Linear Tolerance

tolerance

This setting specifies the permissible variation of certain measurements. For example the diagram shows a tolerance of +/- .005" indicating that the length of the rectangle can be between 1.995" and 2.005". See Tolerances for details. For lowest cost select the largest acceptable value.

Material thickness tolerance

acetal

This setting specifies the permissible variation in thickness of 2D parts. For example, a tolerance of 20% applied to a 1/8" thick sheet would mean that the sheet thickness used for your job could range from 0.1 to .15. For 3D parts select N/A if you want the general linear tolerance (see above) to apply. If you select a percent value, the position of any holes or other features created on the edge of the sheet will be measured from the bottom side of the sheet in accordance with the general linear tolerance. It is usually more economical to use one of the percent values when parts are cut from sheets 0.75 in thick or less.

Edge Draft

edge_draft

Due to limitations of manufacturing processes, edges (exterior and interior) that should be at 90 degrees to their adjacent surface cannot be exactly 90 degrees. This setting specifies the maximum deviation from 90 degrees that you will permit for edges perpendicular to the Top view. For lowest cost, select the largest acceptable value. Larger values reduce cost especially for 2D parts cut from sheets. For example, for a 1/16" thick sheet and a 10 deg edge draft, the bottom side could have only up to .016" more material at edges than the top side. (Tolerances will be applied to measurements on the bottom side.) If you select zero or Default for this setting, the job Tolerance setting will control.

Flatness

potato_chips

This setting specifies how flat the largest outer flat surfaces will be. In particular, all points on those surfaces will be between two parallel planes the specified distance apart. For lowest cost select the largest acceptable value. For example, a potato chip might have a flatness of ~0.5" and a business card ~0.1".

Roughness

phonograph_record

These settings specify the smoothness of the surface (Top & Bottom views) and edge (Front, Back, Right, Left view), measured as a function of the height of the small ridges resulting from the cutting process. The setting you specify may be met by direct machining, polishing, sanding, grinding or any other method unless a specific method is specified. Examples: polished surfaces are often ~1 microinch. Machined parts are often ~63 to ~125 microinch. A phonograph record is ~250 microinch. 

Note: Some manufacturing processes use multiple cutters, so where a cutter change occurs a minor surface discontinuity can appear. Such transition points will be held to a reasonable minimum for roughness settings 63 and smaller. Minimizing such transitions is usually appropriate only for highly visible parts where appearance is a prime concern. 

Process permissions

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