Standoff Height: How Close Should You Be?

The standoff height is the distance between the tip of the mixing tube and the material. A standoff too high causes dimensional problems and alters the top edge created by the jet as it gradually widens in open air.  Standoff too low risks scratching material on rapid traverse between cut paths, or snapping the tube causing downtime, cost, and angry operators.  Standoff height should be approximately the thickness of a coin (varies depending on your nationality, obviously) – about 0.100” (2.54 mm).

Standoff Height

I guess I could end the blog right here, but I think there are a few more things you might want to know about standoff height.

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Dynamic Waterjet

Dynamic Waterjet: The Story of a Problem Worth Solving

Taper left on a part was by far the biggest complaint from our customers across the world. As we have learned in prior posts, the faster you cut through a material with an abrasive waterjet, the greater the v-shaped taper. At the time, the only solution was to slow down your cut speed. The problem was, slowing down only minimized the taper – but rarely get rid of it; and slowing down costs shops a lot of money per part.

Waterjet Technology Overview

So, What Is Stream Lag & Taper?

A waterjet stream acts like a beam when cutting, much like plasma cutting and laser cutting. These types of non-rigid cutting tools have to address the beam flexing and changing within the target material to minimize part cutting errors.

What is taper?

Taper in waterjet cutting is when the entrance width of cut is different than the exit width of cut.

Taper_v2

What is stream lag?
Stream lag causes corner damage when the exit point lags behind the entrance point, shown in the bottom of the part below.

Plasma cut parts often exhibit an upside-down V-shaped taper where the width of cut is wider at the bottom. Laser and waterjet exhibit a normal V-shaped taper (more narrow width of cut at the bottom). Plasma, laser and waterjet can all yield stream lag errors when cutting a part.

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Debunking Common Misconceptions about Waterjets {Part 1 of 2}

What did you say?

I can’t say I’ve heard them all, but I’ve heard a bunch of them: strange misconceptions about waterjets.

It’s not surprising.

After all, we are cutting with a supersonic waterjet stream (often with a garnet sand added to it) and yet it can cut through a foot thick (300 mm) of metal. People say, “No it can’t!” Actually, yes it can.

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How One Small Change Made Waterjet What it Is Today

Today waterjet is one of the fastest growing machine tool processes in the world and has over 30,000 systems installed. But how did it begin? I’ve seen many different claims over the years as to the start of waterjet. There is only one thread – one sequence of events – that I subscribe to, and that is the specific sequence that leads to the commercialization of waterjet for the cutting of soft materials in the 70’s.

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