Machining Tolerance Requirements

(1) The tolerance of unnoted shape should meet the requirements of GB1184-80.  

(2) The allowable deviation of unnoted length is ±0.5mm.  

(3) The tolerance zone of the casting is symmetrical to the basic size configuration of the blank casting.  

Requirements for Cutting Workpiece  

(1) Parts should be checked and accepted according to the working procedure. Only after the inspection of the previous working procedure is qualified can they be transferred to the next working procedure.  

(2) The processed parts are not allowed to have burrs.  

(3) The finished parts shall not be placed directly on the ground, and necessary support and protection measures shall be taken.  The processing surface is not allowed to have rust decay and affect the performance, life or appearance of the bump, scratch and other defects.  

(4) Rolling finishing surface, rolling can not have peeling phenomenon.  

(5) There should be no oxide scale on the surface of the parts after heat treatment in the final process.  After finishing the mating surface, tooth surface should not be annealed  

(6) the processed thread surface is not allowed to have defects such as black skin, knock, random buckle and burr.  

BMT Professional Machining Parts


Operators in machining understand the classification of machining process and the technical requirements of machining process, can better reduce the errors in machining.  Rhyme billiton machining is specialized is engaged in the large frame welding processing, large CNC gantry milling, large plate processing machinery, large precision CNC lathe processing, horizontal CNC machining, precision machinery parts processing, chassis sheet metal parts processing, metal stamping parts processing, such as all kinds of large scale high precision hardware parts of large mechanical processing plant.


The manufacturing errors of machine tools include spindle rotation error, guide rail error and transmission chain error.


1. The spindle rotation error

The spindle rotation error refers to the actual spindle rotation axis of each moment relative to its average rotation axis of the change, it will directly affect the precision of the workpiece being processed. The main reasons for the spindle rotation error are the coaxiality error of the spindle, the error of the bearing itself, the coaxiality error between the bearings, the spindle winding, etc. The guide rail is the datum to determine the relative position relation of each machine tool part on the machine tool, also is the datum of the machine tool movement. The manufacturing error, uneven wear and installation quality of the guide rail are the important factors that cause the error of the guide rail. Transmission chain error refers to the relative motion error between transmission elements at both ends of the transmission chain. It is caused by the manufacturing and assembly errors of each component link in the transmission chain, as well as the wear and tear in the use process. 




2. Positioning error  

Location error mainly includes datum miscoincidence error and location pair manufacturing inaccuracy error.  When the workpiece is processed on the machine tool, it is necessary to select a number of geometric elements on the workpiece as the positioning datum for processing. If the selected positioning datum and the design datum (the datum used to determine a surface size and position on the part drawing) do not coincide, it will produce the datum mismatch error  

The locating surface of the workpiece and the locating element of the fixture constitute the locating pair together. The maximum position variation of the workpiece caused by the inaccurate manufacturing of the locating pair and the mating gap between the locating pair is called the inaccurate manufacturing error of the locating pair.  The manufacturing inaccuracy error of the positioning pair can be produced only when the adjustment method is used, but not in the trial cutting method.

Post time: Aug-01-2021

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