ABB IRB 6620LX, Product Manual

Page: 344 / 360

7.3 Screw joints
General
This section describes how to tighten the various types of screw joints on the IRB
6620LX.
The instructions and torque values are valid for screw joints comprised of metallic
materials and do
not apply to soft or brittle materials.
UNBRAKO screws
UNBRAKO is a special type of screw recommended by ABB for certain screw joints.
It features special surface treatment (Gleitmo as described below) and is extremely
resistant to fatigue.
Whenever used, this is specified in the instructions, and in such cases, no other
type of replacement screw is allowed. Using other types of screws will void any
warranty and may potentially cause serious damage or injury.
Gleitmo treated screws
Gleitmo is a special surface treatment to reduce the friction when tightening the
screw joint. Screws treated with Gleitmo may be reused 3-4 times before the coating
disappears. After this the screw must be discarded and replaced with a new one.
When handling screws treated with Gleitmo, protective gloves of nitrile rubber
type should be used.
Screws lubricated in other ways
Screws lubricated with Molycote 1000 should only be used when specified in the
repair, maintenance or installation procedure descriptions.
In such cases, proceed as follows:
1 Apply lubricant to the screw thread.
2 Apply lubricant between the plain washer and screw head.
3 Screw dimensions of M8 or larger must be tightened with a torque wrench.
Screw dimensions of M6 or smaller may be tightened without a torque wrench
if this is done by trained and qualified personnel.
Article number Lubricant
3HAC042472-001 Molycote 1000 (molybdenum disulphide grease)
Tightening torque
Before tightening any screw, note the following:
• Determine whether a standard tightening torque or special torque is to be
applied. The standard torques are specified in the following tables. Any
special torques are specified in the repair, maintenance or installation
procedure descriptions. Any special torque specified overrides the standard
torque!
• Use the correct tightening torque for each type of screw joint.
• Only use correctly calibrated torque keys.
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344 Product manual - IRB 6620LX
3HAC035737-001 Revision: P
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7 Reference information
7.3 Screw joints