Newbie Needs Help

[FMats]

This is my first time posting and hoping to get some insight,

This is in regards to cutting 4140 material with an automatic circular cut off cold saw using a cermet tipped sawblade.

The cermet tipped blade developed chipping near the corners at standard parameters run. They normally get 10,000 pcs but two blades only produced 600 and 900 cuts per blade due to a failure mode(burr on cut surface). It was 20 degrees below 0 for a few weeks. These bars were coming straight from the outside into the building through a small wall. They were very frozen. Bars were 4’’ round.

Initially I would say it must be something else and not temp. but I could be wrong.

 

[redpicker]

FMats,

With what you have written, I have to wonder that if you brought the bars in through a large wall, would that help? If not, why are you telling us the size of the wall?

rp

 

[TVP]

FMats,

The temperature of the bars will certainly affect the durability of the saw blade, but I would not necessarily say that it explains a difference on the order of 10x (10,000 cuts vs. 1,000 cuts). The material will be about 10% stronger/harder at that temperature compared to normal ambient/room temperature. Have you contacted your consumable supplier to get their feedback?

 

[FMats]

Will do, Thanks for advice!

 

[tomwalz]

If you're using the same tool supplier, ask them if they have changed saw tip suppliers.

With the huge jumps in the price of tungsten and other raw materials many tool manufacturers are looking at new suppliers.

The substitutes are not always 100% successful.

Thomas J. Walz
Carbide Processors, Inc.

http://www.carbideprocessors.com

Good engineering starts with a Grainger Catalog.

 

[1gibson]

How's this for a theory: Cold bar, start the cut. Bar heats up locally, the gap from the initial cut closes as the bar expands and this squeezes the blade.

Like trying to chainsaw a tree limb from the underside.

I'd give that theory a 4/10 maybe, but doesn't hurt to consider it.

 

[farmENGR]

1gibson. This actually happens in the sawblade world. When bars or tubes that are not stress relieved and have residual streses present in them they can actually close up and pinched the blade. And if a blade is rotating very very fast through there well....you may have just kissed all the teeth goodbye.

This theory does happen!

thanks,

 

[FMats]

Thanks to all!! I really appreciate it