Min/Max Roll Gap Drift in Danieli Pinch Rolls (Wire Rod Mill) – Need Troubleshooting Advice

[Mohamed_AN]

After initial adjustment, the minimum gap setting on our Danieli pinch rolls drifts during operation, causing misalignment and poor wire guidance. Inspections (bolts, bearings, alignment) show no obvious faults. Seeking expert insights on root causes and corrective actions.

Detailed Description:​

1. Equipment:
   • Danieli pinch rolls in a wire rod mill.
   • Function: Guides the wire between passes with adjustable min/max roll gaps.
2. Problem:
   • After few hours (2 or 3h) of operation, the minimum gap widens unexpectedly (Problem occurs when rolling small diameters 5.5 and 6mm).
   • Leads to vibrations, wire twisting, or uneven wear.
   • Issue persists despite re-tightening bolts and checking pneumatic actuator.
3. Suspected Causes (Need Validation):
   • Thermal expansion of components ?
   • Wear in internal adjustment mechanisms (e.g., screws, shims)?
   • pneumatic system fluctuation ?
4. Already Checked:
   • Bolt torque, bearing/bushing, actuator condition, roll alignment.
   • No visible damage or lubrication issues.

Questions for Experts:​

1. Has anyone faced similar gap drift with Danieli rolls? How was it resolved?
2. What components should we inspect more closely (e.g., adjustment screws, sliding blocks)?
3. Are there preventive maintenance steps to mitigate this (e.g., recalibration frequency)?

1. What components should we inspect more closely (e.g., adjustment screws, sliding blocks)?
2. Are there preventive maintenance steps to mitigate this (e.g., recalibration frequency)?

 

[desertfox]

Hi there

Have you or anyone from your company contacted Daneili?

 

[3DDave]

They look wonderful when working correctly:

 

[Gr8blu]

The OP indicates that the gap widens, and they have to re-torque clamping bolts.
1. Have one or more bolts loosened (e.g. backed out), or has the bolt itself lengthened? Both can be measured and can give an indication of what is happening.
2. Is there a timer setting for the actuator control (or other "gap" controller) that might not be long enough for the time it takes to process material?
3. Is the product (wire rod) not impacting the rolls at a consistent (and desired) angle, thereby producing unexpected additional force in one direction or another?
4. Does the unexpected change occur during when a certain setting/spacing for the rolls is used - or on multiple settings?

Maybe most importantly - is this a new mill, or a new-to-you mill (i.e. used)? If used:
a) what has been the past maintenance and operating history?
b) was the mill transported from one site/location to another - and did all the parts arrive?

 

[3DDave]

Imagine if there was a video of this adjustment being made, one of the mill running when the problem shows up after that adjustment, and then a video showing how loose the parts have gotten.

 

[btrueblood]

What Gr8blu said - "1. Have one or more bolts loosened (e.g. backed out), or has the bolt itself lengthened? Both can be measured and can give an indication of what is happening."

You should be marking the bolt heads after the adjustment to see if they are rotating, and/or checking bolt length periodically, if not during operation. If you think it might be thermal expansion of the bolts and the bolt joints (but can't measure the length directly), put some thermocouples on the bolts and adjacent hardware, and monitor the temperatures during a run.