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Screener meshes breaking

Porter238

Member
Joined
Jul 3, 2015
Messages
10
Location
scotland
Hi folks I'm new here, I'm currently running a sandvik robotrak screener and having a terrible time with meshes shearing at the hooks. I've never had this problem before, I put 3 new meshes in this morning, an hour later one had 3 hooks sheared off. Help please
 

Porter238

Member
Joined
Jul 3, 2015
Messages
10
Location
scotland
Can meshes be too tight? It'd make sense the way there sheared but what should they be tightened too
 

lantraxco

Senior Member
Joined
Jan 1, 2009
Messages
7,704
Location
Elsewhen
I'm no expert and I haven't changed any screens in twenty years, but back then the guys I worked for would kind of tune them like a piano string, when you hit the screen with the your hand on the finer wire ones, or a mallet on the heavier ones, you could kind of tell when the bounce was right. It's easy to tell if they're too loose, when you start the shaker running you can see the wire bouncing off the frame under it. And of course you want to try to keep the tension equal all along the whole mesh.

Sorry I can't be more help, maybe someone with more recent and varied experience will chime in :)
 

Porter238

Member
Joined
Jul 3, 2015
Messages
10
Location
scotland
No, any help is great. I've ran various screeners and never seen this before, it's 125mm squares so you can imagine there made of 12mm bars and there shearing like piano strings
 

lantraxco

Senior Member
Joined
Jan 1, 2009
Messages
7,704
Location
Elsewhen
Wow, heavy stuff... I seem to remember the heavier screens didn't require as much tension just due to the mass, but as I said it was a long time and many pints ago :rolleyes:
 

Cmark

Senior Member
Joined
Jan 2, 2009
Messages
3,176
Location
Australia
I've seen meshes break in the middle when the cushion rubbers weren't in good order but I've not seen a chronic problem with them breaking at the hooks.

It sounds like a problem with the manufacturing. I'd speak to your supplier and ask a few questions.

Are they sourcing the mesh from a new supplier?

Have they got a new man forming the hooks? Maybe he's getting them too hot and quenching them? (Assuming they form the hooks hot).

If they form the hooks cold, have they put the correct knife in the press brake?

Can you post a photo of the break?
 

Porter238

Member
Joined
Jul 3, 2015
Messages
10
Location
scotland
Hi there, I'll take pictures on Monday, I fitted one screen on Wednesday that was lying from last year and I replaced all 3 yesterday with new ones so there not the same batch, can they be over tightened?
 

Cmark

Senior Member
Joined
Jan 2, 2009
Messages
3,176
Location
Australia
I suppose they can be over tightened but you would be putting a lot of effort in to do so. It's been maybe 10 years since I tampered with screens but I don't suppose the technology has changed much. Tighten them until they stop vibrating on the cushion rubbers, then a bit more, then that's it.

Are they breaking at the edges or in the middle? Just thinking is it possible you've got your ' banana bar' in back to front?
 

Porter238

Member
Joined
Jul 3, 2015
Messages
10
Location
scotland
There's no set pattern with the way there shearing but on this robotrak it's not a banana bar, the bar is on slides with 3 bolts on the outside of the screen box that's pulls it tight
2053ac10b56923f584bef2179a650d65.jpg
 
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