Screw Joints - ABB Robotics IRB 6790 Product Manual

7 Reference information

7.4 Screw joints

7.4 Screw joints
General
This section describes how to tighten the various types of screw joints on ABB
robots.
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.
Stainless steel screws
Stainless steel screws should be secured by hand at least 2 turns before using an
electric screwdriver.
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:
Lubricant
Molycote 1000 (molybdenum disulphide grease)
Tightening torque
Before tightening any screw, note the following:
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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.
• 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
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Article number
3HAC042472-001
Product manual - IRB 6790
3HAC063331-001 Revision: B