Laser cutting pickled and oiled material
In my facility we purchase "laser quality plate" that is hot rolled material with rather light mill scale when compared to discrete plate that we might cut on our plasma/oxy machines. I'm trying to change the process for a particular part we manufacture to using pickled and oiled material to eliminate the need for abrasive blasting down stream.
Some of the concerns about this change are:
Material cost, almost irrelevant based on current quotes for the material in question
Laser lens life, it's believed that oiled material will cause fogging and or degrade lens life
I was under the impression that PO material was higher quality, which leads to higher cut quality, and something of a standard for laser material? I don't have any data to refute the concern about lens life, so I'm looking for input here.
Last edited by kuraki556; 06-18-2012 at 01:50 PM.
I work some were that cuts over 80% pickled and oiled. Assuming your running a relatively recent laser, with a sealed + purged beam path on a a machine with good extraction there really is no way for the oil vapour to get near the lens. Hence i have to wonder who invented that gem, maybe the non pickle and oiled steel suppliers sales man? That lens is a consumable, just the heat the beam dumps in it will gradually distort it into rubbish just like all of the beam path optics. The mirrors + lenses don't last forever.
The biggest issue i have with the p&o compared to the light scaled plate is its love for mig splatter. Its not a issue on the stuff that's well oiled but some of ours comes in pretty near dry some times (the oil is pretty light and noticeably drys of on plate that's been in the shop for a month or so!). Hence being akin to a clean blasted finish it needs generous use of anti splatter if your going to mig it. It can be very soft - buble gum like to drill too :-( Thankfully the new Mitsubishi laser has far better small hole capability than the old amada.
Depending on actual finish, it may still require blasting to meet certain paint standards. The P&O finish is pretty slick still. Does look great zinc plated or passivated though!
Hot Rolled vs HRPO
We are a laser cutting system manufacturer. In the early days of lasers when power was at a premium we recommended HRPO all the time in 3/8" and heavier. Today we recommend laser quality hot rolled, IPSCO (SSAB) if you can get it. In those days scale could be a real problem. When the scale varied from none to the thickness of a dime across the sheet the cutting was challenging. The thin tight consistent scale on today's laser quality hot rolled plate is fine for laser cutting.
In general the oil on the material adds carbon or heat to the process. You will probably find that is easier to cut small holes and intricate features in hot rolled compared to HRPO. Most often you will find that the process you use to get rid of scale does a nice job on the oxide on the edge of the part as well.
One other option is SCS. This is a process used by some steel service centers to remove most of the oxide through a brushing process. It leaves only the very bottom layer. The steel looks like HRPO but it has no oil. It is somewhat rust resistant. It cuts like high quality laser steel. see: SCS Steel Surface Treatment Enhances Finish for Fabrication
See plate cutting on our YouTube site: CincinnatiWeb - YouTube
Also see our web site if you are interested: CINCINNATI