3.2 Safety Design

							3.2 Safety Design                                          Apart from these treatment methods, alkali coloring
                                                           treatment (blackening), color alumite treatment, and
                                                           the like are provided to areas other than raceways to
3.2.1 Determining which materials to use                   improve appearance.
Linear motion systems are used in a variety of
environments. It is therefore important to use             When using a surface-treated linear motion system,
materials that best suit your particular environment.      please set the safety factor to a higher level than for
                                                           non-treated linear motion systems.
In locations that require corrosion resistance, products
made of stainless steel can be a good choice. (Model
                                                           3.2.3 Contamination Protection
numbers with “M” indicate that the models are made
                                                           In the operation of linear motion systems,
of stainless steel. For details, see the description
                                                           contamination protection is critical. Inclusion of dust
under the respective model numbers.)
                                                           and foreign matter in a system causes abnormal wear
                                                           and shortens the system’s service life.
The stainless steel used in models designated with “M”
is martensitic and therefore superior in corrosion
                                                           Where dust and foreign matter inclusion is likely, a
resistance. In other words, corrosion resistance does
                                                           high-performance sealing device or dust control device
not deteriorate over time. Stainless steel models are
                                                           most appropriate for the ambient conditions must be
thus suitable for use where general corrosion
                                                           provided.
resistance is needed. Moreover, because stainless
steel prevents precision from deteriorating, it makes it
                                                           1) Special seal for linear motion systems
possible to produce high-precision products.
                                                           Highly wear-resistant, synthetic rubber seals that
                                                           prevent contamination from dust are available from
                                                           THK. Various seals are specially designed for the
3.2.2 Surface Treatment                                    respective linear motion system models (Figs. 12 and
The rails and shafts used in a linear motion system can    13).
be surface-treated for the purposes of rust prevention
and good appearance.                                       For the seal designations, see “Dust Control” under the
                                                           section for the model number in question.
THK provides THK AP Treatment as a high-quality
surface treatment for linear motion systems. THK AP        For locations with harsh ambient conditions, special
Treatment is intended chiefly to reinforce anticorrosive   bellows and covers are available from THK. For
properties, and comes in the following three types.        details, see “Accessories” under section for the model
                                                           number in question.
1. AP-CF
                                                           To provide contamination protection measures in an
AP-CF is a compound surface treatment consisting of a
                                                           atmosphere subject to scattering of cutting chips, oil,
black chrome film coating and a special fluorocarbon
                                                           and the like, in addition to bellows and covers, use a
resin coating. It is suitable where high corrosion
                                                           telescopic cover or large bellows that can cover the
resistance is required.
                                                           entire system.

2. AP-C                                                    2) Special bellows
AP-C is an industrial black chrome film coating            Special bellows are standardized for use with LM
intended to improve corrosion resistance. It is cheaper    Guides (Fig. 14).
than using martensitic stainless steel and provides
greater corrosion resistance.                              Upon request, we can produce special bellows for
                                                           linear motion systems other than LM Guides, such as
                                                           Ball Screws and Ball Splines. For more information on
3. AP-HC
                                                           these special bellows, please place an inquiry with THK
AP-HC is equivalent to industrial hard chrome plating.
                                                           (Fig. 15).
It offers practically equivalent corrosion resistance to
that of martensitic stainless steel, while providing a
very hard coating film of 850 HV or more. It is
therefore superior in terms of wear resistance.


                   A-20
       End seal




                                                                                             A-I
                                                Seal




       End seal                                 Seal




Fig. 12 Dust Control Seal for LM Guides      Fig. 13 Dust Control Seal for Ball Splines




 Fig. 14 Special Bellows for LM Guides    Fig. 15 Special Bellows for Ball Screws and Ball
                                                              Splines


                                                                  A-21