preface

In the machining workshop, have you ever encountered such confusion: the newly bought CNC tool is obviously sharp enough, but it collapses after a few workpieces are cut; Finally increased the cutting speed, but the surface of the workpiece became potholed; The coating knife is used, and the coating falls off like peeling……In fact, these problems are likely to point to the same key process——Tool passivation treatment. mention“passivation”Many people's first reaction is“Let the knife be dull”This is a big mistake. Let's have a good chat today, this sounds“Contrary to common sense”What are the doorways hidden.

01.Tool passivation: No“Become dull”but“optimize”

First of all, clarify a misunderstanding: knife passivation is not to dull the sharp edge, but to let the knife go “More durable and reliable”core process.

To put it simply, tool passivation is a process of CNC tools after fine grinding and before coating“Compulsory”The core is to repair the microscopic defects of the cutting edge through deburring, leveling the cutting edge, fine polishing and other operations. And there are many more“alias”, such as edge strengthening, edge honing, or professional“ERdispose”, but the essence is the same thing: let the cutting edge of the knife reach“Sharp and strong”The ideal state.

02.Why do you have to do passivation?

The knives ground by ordinary grinding wheels or diamond grinding wheels look quite sharp, but in fact, they are all under the microscope“Minor wounds”——Tiny blades and jagged chips, like the edge of freshly broken glass, seem sharp but fragile.

these“Invisible wounds”It is a big problem when cutting: the high-speed rotating tool rubs against the workpiece, and the gap will continue to widen, at best, the tool will wear out, and the edge will break directly. More importantly, today's machining is increasingly pursuing high-speed cutting and automation, which requires extremely high tool stability. Especially for coated tools, if they are not passivated before coating, the coating will follow the notch of the cutting edge“infiltration”, the slightest vibration will fall off in pieces, but shorten the life.

03.Passivation target

To put it bluntly, passivation treatment is to do it on the cutting edge of the knife“Microplasticization”: Smooth and round those sharp but fragile microscopic notches to retain sufficient cutting sharpness and make the cutting edge become“Tough and resistant to manufacturing”。

Imagine that the edge of an unblived knife is like an overly sharp knife, and it is easy to break when cutting hard things; And excessive passivation will become“Blunt axe”, cutting labor. High-quality passivation treatment is to find this perfect balance——Make the knife easy“bite”The workpiece can maintain combat effectiveness for a long time.

04.Changes in the tool after passivation

Professionally passivated tools will usher in an all-round upgrade in performance, and these three changes are the most intuitive:

●Edge“Makeover”from“Rough boy”change“Smooth gentleman”：

The burrs and tiny chips at the edge of the edge are completely removed, turning into a rounded and smooth arc. This not only reduces the amount of cutting time “Head toe”, greatly reducing the probability of breaking the blade; It can also make the contact between the tool and the workpiece more even, and the surface finish of the processed workpiece is directly upgraded, and there is no need to rework for rough grains.

●Chip removal chutes“Desilting and polishing”, chip removal speed“Lightning fast”：

After the chip flute of the tool is evenly polished, the surface becomes as smooth as a mirror. This means that the chips go more smoothly“Slip away”, will not get stuck in the groove to hinder cutting, and can even support higher cutting speeds. At the same time, the smooth surface can also reduce the amount of tool and workpiece material“occlude”risk, cutting forces can be reduced at most40%, which is more labor-saving and stable to process.

●coating“Icing on the cake”, wear-resistant and heat-resistant“pairbuff”Blessings:

After coating, there will inevitably be some on the surface of the cutter“Small pimples”(droplets of coating condensation), these small pimples increase frictional heat generation and limit cutting speed. Passivation polishing can grind away these small bumps while leaving a fine surface at the same time“Small pits”。 These pits are like one by one“Oil storage tank”, which can adsorb more cutting fluid, greatly reduce the cutting temperature, and make the tool more suitable for high-speed cutting“Calm down”, the life span will naturally be longer.

summary

It turns out that knife passivation is not“Drag your legs”, but let the CNC tool give full play to its full potential“God assisted”。 It uses seemingly simple grinding and polishing to solve the most troublesome problems of wear, precision and efficiency in processing. Next time you will encounter a knife“Ephemeral”workpiece“rough”, you might as well take a look first: Is this key passivation process missing? After all, on the way to efficient machining, let the tool“Healthy work”, is the most cost-effective investment.