Technical Information

TOLERANCES

K-zell Metals, Inc. is not a precision sheet metal house.  Finished fabrications and press brake formed parts are typically held to +/- 0.062”.  Rolled parts such as rolled tube arches or angle ring segments are usually held to +/-0.25”.  Rolled cylinders are usually held to +/- 0.125” on the circumference and are round with in about 5% of the diameter.

ANODIZED PARTS

(Color match on anodized parts) - Anodizing changes as the composition of the aluminum changes. This is most problematic at welded joints where the weld filler material is usually a significantly different alloy that the base material. The result is that the weld is generally a darker gray after clear anodizing than the adjacent material. The problem is minimized by filler wire selection and joint design, but cannot be completely eliminated.

INSPECTION

Final inspection and acceptance of polished materials must be made at K-zell Metals factory.

CUTTING TOLERANCES

Parts processed with CNC cutting systems may have dimensional variations as a result of the mechanical components on the particular system, the cutting process and the material being cut.
The robotics of the particular cutting system has both repeatability and location tolerances. 
The cutting process may not cut truly perpendicular to the surface of the plate.  The kerf in the Plasma cutting process widens as it goes through the material and results in a 2-5 degree taper on the cut edge.  The speed and direction of the cut also influences the kerf width.
The material may move on the table as the part heats up from the cutting process causing dimensional deviations.

Tolerances for laser cut parts vary by material type, part size and cutting parameters.  In general most parts can be held within +/- 0.015”.  Please, inquire about special tolerance or tolerances on parts with any dimension over 36”.

Tolerances for plasma cut parts are typically +/- 0.062”

PRE-ANODIZED

(Crazing in pre-anodized sheets) - Parts from pre-anodized sheet, have minor cracks in the anodized coating that form when the sheet is formed. This cannot be eliminated.

SHEARING

(Material distortion from shearing) - The process of shearing introduces stresses in the material being cut and can also release stresses already in the material. The change in the stress level usually results in some distortion of the cut part. Shearing narrow strips of 2" or less in width, will generally result in the part having a twist. Heavy sheet and plate will tend to have a bow in the finished part. Predicting the amount of distortion is very difficult. It changes with material type, heat treatment and thickness. K-zell Metals will use what shop practices are available to minimize the distortion, but the distortion cannot be eliminated.