reverse taper

[dava]

I need some help. On our plasma table we are currently trying to cut some 1/2 holes on the top side they measure .502 but on the bottom where they rest on the table they are .540. I have never seen it cut wider on the base and narrow on the top, normally it is reversed. Any ideas?

[acourtjester]

may be cutting to low with cut height

[muzza]

or too slow

[Largemouthlou]

Rather have it big then small!! LOL

[Gamelord]

Most of the time this is caused by not having the proper cut height.

[DezertBlingMoto]

This is where I get really confused with machine torches. At a lower height wouldn't the torch be more controlled then when lets say you might be .1+ give or take . I have not been able to get a clean 1/2" hole. Really close but not a flush top to bottom hole.

[Capstone]

I need some help. On our plasma table we are currently trying to cut some 1/2 holes on the top side they measure .502 but on the bottom where they rest on the table they are .540. I have never seen it cut wider on the base and narrow on the top, normally it is reversed. Any ideas?

How thick is the metal? There's a rule of thumb when it comes to the size relative to the thickness that can also have a big impact. Jim Colt has a thread on cutting holes and how to improve quality. keyword holes and Colt might get you there.

[Gamelord]

Another thing may be the direction you are cutting. Clockwise or counter clockwise. One way will put more of the bevel on the drop, the other direction will put more of the bevel on the target piece. Check your cut direction and see if that fixed the issue.

[gary42095]

you also need to post :
table brand
plasma cutter brand
material being cut
cuts spec
that way it will narrow down the issues your having.
also pics of piece might help as well.
nozzle ,electrode worn? shield worn/plugged
is taper consistent in hole? only in the smaller holes?
have you checked cut height with book spec? reduced speed , turn thc off
more info will steer you to better answers

[jimcolt]

Yes...I would like to know what cutter you are getting a reverse taper with.....as this would be a major breakthrough in plasma cutting. Normally the bottom of the hole is smaller than the top! What gases, what thickness material, etc.

Jim Colt Hypertherm

[dava]

It was with stainless 304 1/4" the speed was set too slow on the cut, We are using an ALLtra plasma cutter.

Do you have any suggestions for reducing taper on holes and improving quality on 304. We were told by the techs to overcut the holes.