benefits of a great finish on a barrel liner

The Benefits of a Great Finish on Barrel Liners

Machining special shapes such as complex extrusion dies, or the grooves in barrel liners, is accomplished by Electrical Discharge Machining or EDM. A small wire laces through the steel, cutting it with very precise accuracy to tolerances of .0004. Parts formed using the EDM process have a very distinct color and surface finish. Smooth to the touch, the finish can be held to just a few microns and is occasionally even better than a ground finish. When we viewed an EDM cut surface under a microscope at Diamond America, however, we spotted minute peaks and valleys that meant there was still scope for some improvement.

Further tests in our lab on dies cut using EDM revealed an astonishingly vast difference between raw parts, straight after cutting, and those that had been subsequently hand polished. Throughput rates jumped on the hand polished dies, compared to considerable drag experienced on the unpolished ones.

This inspired us to further investigation – what if we polished our liner grooves?

Removing the EDM finish from liners created the same results. Material did not clog in the grooves, allowing easier cleaning. Simple glass beading and hand polishing eliminated all stickiness.

benefits of a great finish on a barrel liner

What does all this mean for you?

  • Higher Output: Less drag and friction in the die or barrel means that feed material moves more quickly throughout the process.
  • Faster Cleanup: Easier removal of material from screw, barrel and die makes for rapid cleaning and reduced changeover times.
  • Shorter Break-in: Pre-polishing of surfaces means that there is no waiting time for internal smoothing. Finish quality is immediate.
  • Better Final Product: Improved material flow fills die corners without tearing and yields an end product that is truer to the actual die shape.


To find out how our engineering excellence can benefit your operation now
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