9.4 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. It is recommended by ABB for M6-M20 screw joints. 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.
Generally, screws are lubricated with
Gleitmo 603
mixed with
Geomet 500
or
Geomet 702
in proportion 1:3.
Geomet
thickness varies according to screw
dimensions, refer to the following.
Geomet thickness
Lubricant
Dimension
3-5 μm
Gleitmo 603
+
Geomet 500
M6-M20 (any length except
M20x60)
3-5 μm
Gleitmo 603
+
Geomet 720
M6-M20 (any length except
M20x60)
8-12 μm
Gleitmo 603
+
Geomet 500
M20x60
6-10 μm
Gleitmo 603
+
Geomet 720
M20x60
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 Molykote 1000 or Molykote P1900 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.
Continues on next page
624
Product manual - IRB 6720
3HAC085697-001 Revision: C
© Copyright 2023 ABB. All rights reserved.
9 Reference information
9.4 Screw joints
Summary of Contents for OmniCore IRB 6720
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