Machine positioning accuracy is not part accuracy
Understand what a catalog accuracy figure can tell you.
SMT editorial guide · 3 min read
Read the label next to the number
Catalog positioning or repeat positioning accuracy describes machine-axis motion under stated conditions. It does not directly specify the radius, contour or dimensional tolerance of a finished part. Keep the axis name and type of accuracy with the figure when comparing machines.
Define part measurements separately
Your part may need a controlled radius, end position, arc angle, twist limit or fit against a template. State those requirements on the drawing. Decide which surfaces are datums and whether inspection takes place after unloading and subsequent operations. Otherwise different measurement methods may appear to disagree.
Consider the complete process
The result depends on the section, material condition, tooling, support and setup. Springback means the unloaded part must be evaluated in its final state. A favorable axis figure alone does not establish that a thin-walled or asymmetric section will hold the required geometry.
Compare evidence for your profile
Request a trial with representative material and a stated inspection method. Record the configuration and adjustments between passes. Agree the scope if multiple samples are needed to assess consistency. Avoid treating an isolated photograph as a quantified accuracy report.
Put acceptance criteria in writing
Distinguish catalog machine data from acceptance requirements for your part in the test and sales documentation. SMT can review the drawing and help identify which measurements to discuss before a sample trial.
Which machine fits your profile?
Send a drawing or clear section photos, material, wall thickness and target radius. Our engineers will review the job and recommend a machine and tooling arrangement.
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