Has this metal been laser cut?

[rcx132]

I've been using an eBay laser cutting service quite a bit lately, but the latest batch has me questioning if it’s truly laser cut or maybe done with a high-fidelity plasma cutter. Would you take a look? I’m seeing beam marks typical of plasma cutting, along with some extra funny lines that weren’t in the DXF files. It also failed to cut a large font intended for laser cutting; the centres of many letters fell out due to inaccurate cuts.

 

[Barking Mat]

Plasma cut I think.

 

[Kram]

Does look like plasma with the tapered one side ripple lines.

 

[Onoff]

Monkey with a gas axe...

 

[julianthegypsy]

The first picture indicates that there are line breaks in that slot so it thinks it's cutting open contours and piercing from the outside instead of one piece from the inside. I've had that problem before and had to zoom in until the part was the size of a house to find the break! That would be the same for laser or plasma.

 

[m_c]

Going by those lead in moves, I'd say that was Plasma. The cut width looks too wide to be laser.

 

[Agroshield]

I've had that problem before and had to zoom in until the part was the size of a house to find the break...

A simple way to verify the dxf before you sent it out is to make the contours polylines (not lines and arcs) and then query the 'closed' flag of the polyline.

 

[Onoff]

A simple way to verify the dxf before you sent it out is to make the contours polylines (not lines and arcs) and then query the 'closed' flag of the polyline.

What's the AutoCAD command to verify a polyline, I've forgotten?

 

[rcx132]

This explains the low cost then. The cuts are also 0.5mm off, which I noticed early on and had me a bit confused, now I know.

 

[Agroshield]

What's the AutoCAD command to verify a polyline...

I do not know a command as such. It is a property of the polyline (right click, choose properties). It has a 'closed' property that is either true or false. I think you can keep the properties window open, so as you select any item, it updates for that item.

 

[Erie Fred]

I've been using an eBay laser cutting service quite a bit lately, but the latest batch has me questioning if it’s truly laser cut or maybe done with a high-fidelity plasma cutter. Would you take a look? I’m seeing beam marks typical of plasma cutting, along with some extra funny lines that weren’t in the DXF files. It also failed to cut a large font intended for laser cutting; the centres of many letters fell out due to inaccurate cuts.

View attachment 471165 View attachment 471166 View attachment 471168

What service did you request ?
what tolerances did you pay for ?

 

[Onoff]

What service did you request ?
what tolerances did you pay for ?

Budget Stevie Wonder Halloween Special.

 

[rcx132]

What service did you request ?
what tolerances did you pay for ?

Well it's advertised as laser cutting. The cost is low... very low.. about three times cheaper than the next cheapest service I found. And now I know why.

It's accurate enough for most of my needs but the last job was to laser cut my kids names into the light fixtures on my buggy and that messed up.

 

[Kram]

Have a link to it? May be useful even if the quality is less good.

 

[rcx132]

Have a link to it? May be useful even if the quality is less good.

https://www.ebay.co.uk/itm/266770895596

Hope it's useful.

 

[Brad93]

laser that is set up wrong or needs new consumables

 

[Erie Fred]

Well it's advertised as laser cutting. The cost is low... very low.. about three times cheaper than the next cheapest service I found. And now I know why.

It's accurate enough for most of my needs but the last job was to laser cut my kids names into the light fixtures on my buggy and that messed up.

"Laser Cutting"....no tolerances on size, location, edge angle, contour finish .
You have a wide open contract from what i can see.
It could be it was cut by a company called "laser cutting" ...with no lasers involved.

 

[Welderpaul]

Brad's right, that is laser cut, not plasma, but badly set up.

The stop/starts are in the parent material rather than the waste, and there's a pierce on the edge of the parent material.

There's a set of sharks teeth on the last pic which is down to incorrect laser set up or a lack of maintainance of the machine. You can get sharks teeth on parts off high-end machines, mostly it doesnt matter as a quick flap-over and they have gone, but these needed to be recut.

Someone's cut those, picked them off the bed, seen they are cr@p, but sent them out regardless, that's the worst bit.

 

[Brad93]

100% what paul said

 

[Kram]

If thats the case it would be interesting if they reply should somone offer them a link to the forum for constuctive critism?

I have a couple of designs brewing that might suit laser cutting and the price for that seems good.