The 90‑degree notching machine performs V‑shaped stamping cuts on square tubes and rectangular tubes for subsequent 90‑degree corner bending.Edge chipping includes notch‑edge cracking,material spalling,galvanized‑layer peeling and micro‑fragmentation at incision corners.Zero‑chipping is an ideal processing target.Under ideal operating conditions,chipping can be greatly suppressed,yet complete absolute zero‑chipping cannot be fully guaranteed by the equipment itself.Final quality is jointly determined by pipe material,wall thickness,die clearance,blade sharpness and stamping parameters.
For low‑carbon thin‑to‑medium‑wall ordinary square tubes,with sharp notching blades,reasonable die clearance,moderate stamping speed and stable clamping,the 90‑degree notching machine can achieve nearly chip‑free notching results.The incision edge remains continuous,without obvious cracking or spalling.Such workpieces can be directly bent for guardrail frames and conventional brackets,meeting general production requirements.Galvanized pipes can also keep most galvanized layer intact if parameters are optimized,only generating tiny local micro‑peeling that does not affect assembly performance.
However,multiple conditions will trigger obvious edge chipping.High‑strength hard materials have poor ductility and are prone to notch‑corner chipping under impact stamping.Too‑thin pipe walls lead to edge tearing and fragment spalling;overly‑thick pipes bear huge shearing force and produce crack‑like chipping at notch root.Worn blunt blades do not cut material cleanly but tear it apart,bringing severe chipping and burrs.Mismatched upper‑lower die clearance is another major cause:too large clearance causes extrusion fracture and chipping,too small clearance accelerates blade wear.Twisted pipes with unstable clamping will bear partial offset load during stamping,leading to unilateral edge chipping.
Galvanized square tubes face special risks.The hard galvanized layer is brittle.Even when the steel substrate is well‑cut,galvanized‑layer chipping and peeling often occur at notch edges.This is a material‑layer characteristic rather than pure equipment failure.
There are inherent process limitations.Mechanical stamping notching is a shearing‑separation process.Micro‑cracks and micro‑chipping on a microscopic scale are difficult to eliminate completely.The machine can only control macroscopic visible chipping,not achieve absolute zero‑damage on micro‑level.For high‑decorative‑grade products requiring perfect edges,post‑processing trimming and polishing are still necessary.
A set of practical measures can minimize edge chipping.Select pipes with suitable wall‑thickness and material hardness within machine rated range.Pre‑straighten deformed pipes to ensure full close‑fit clamping.Regularly inspect,sharpen or replace dull notching blades.Fine‑tune die clearance according to wall thickness.Reduce stamping speed appropriately to allow steady material shearing instead of violent impact.For galvanized pipes,reserve local anti‑rust treatment allowance for notch areas.Avoid one‑shot heavy‑impact forming for high‑strength pipes.
In conclusion,the 90‑degree notching machine can greatly reduce visible macroscopic edge chipping under matched material,sharp dies and standardized operation,but cannot achieve 90%absolute chip‑free processing.Hard high‑strength material,improper clearance,worn blades and unstable clamping will induce obvious chipping.Galvanized pipes are prone to coating peeling at incision.Micro‑level tiny defects are objective for stamping process.High‑appearance‑requirement workpieces need corresponding post‑processing finishing.
References
1.APA 7th
Wang,L.(2024).Causes and suppression methods of pipe edge chipping for 90‑degree notching machine.
2.MLA 9th
Wang,Lei."Causes and Suppression Methods of Pipe Edge Chipping for 90‑Degree Notching Machine.
3.GB/T 7714‑2015
WANG L.Causes and suppression methods of pipe edge chipping for 90‑degree notching machine.
