Special
Slideways
Machine Tool Sector
/ SPECIAL SLIDEWAYS
At Zorrotz Legazpi S.L.L. we have been producing Machine Tool Slide-Ways for the past few decades.
The Special Slide-Ways manufactured by Zorrotz Legazpi S.L.L., are the ideal solution for those application where long durability, high stability and a strong wear resistance are needed, when standard linear guides, equipped with rollers or bearing, are not sufficient to guarantee the desired quality.
The experience accumulated by Zorrotz Legazpi S.L.L. performing heating treatments, guarantees the correct implementation of the process and a homogenous hard-ness all over the Slide-Way´s surfaces. Through hardening treatment is carried out exclusively in our facilities by ex-perienced Zorrotz staff.
/ TYPES OF SLIDEWAYS
Flat Slide-Way
Thin
Flat Slide-Way
with Bores
Prismatic
Slide-Way
Slide-Way with
Multiple Sliding Surfaces
/ GEOMETRIC TOLERANCES
/ PARALLELISM
By “Parallelism” we identify, the maximum error between two parallel flat surfaces.
This characteristic is critical for the Slide- Way, due to the fact that any error of parallelism, is directly transferred to the machine´s X, Y, Z reference planes, having a direct impact on the quality and tolerances the machine can achieve.
/ SQUARENESS
As the parallelism, the squareness is another important characteris¬tic for Slide-Ways. Any dimensional error in squareness, has a direct influences in the positioning of the headstock or the carrier, therefore in tolerances and quality the machine will eventually achieve.
The squareness, defines the absolute value of the maximum error between two perpendicular surfaces.
/ FLATNESS
The flatness defines the maximum allowable error between an “ideally flat surface” and the real surface we need to measure the flatness of. Flatness can be measured with the Slide-Way in two dif¬ferent positions:
- Free state
- Fastened to the machine tool bed
As shown in the pictures, depending on the measuring method (Free state or Fastened), the flatness of the same Slide-Way can change remarkably.
FREE STATE SLIDEWAY → FASTENED SLIDEWAY
The flatness of the Slide-Way when “fastened”, can be shown as:
SLIDE-WAY FLATNESS <= Bed flatness + Slide-Way Parallelism
The importance of the flatness in Slide-Ways and the method of the measurement, depends on the final use and the type of machine. Generally, the flatness should be measured always after having fastened the Slide-Way on the machine-tool bed.
/ ROUGHNESS
The roughness is the property describing the state of any ma¬chined surface. Any tool machining process, create furrows on the machined surface. Depending on the tool type and speed used during the manu¬facturing process, the size of the resulting furrows changes. The size and shape of these small irregularities, defines the sur¬face roughness.
How to measure
The rougness of a surface is measured by a specific instrument called Profilometer, or Surface Roughness Tester. The procedure of defining the roughness, consist in recording the profile of the surface and measuring the amplitude of its peaks.
/ TOLERANCES AND PRECISION
Thanks to the flexibility of our production processes, we are able to produce guides with different finishes and accuracies to suit the needs of our customers.
The following chart shows two sizes for each of the dimensional characteristics listed.
| Geometric Tolerances | Estandard | Precision |
|---|---|---|
|
PARALLELISM |
< 0,02 |
< 0,01 |
|
PERPENDICULARITY |
< 0,05 |
< 0,005 |
|
FLATNESS |
< 0,15 / Mt |
< 0,005 / 300mm (0,015 / Mt) |
|
ROUGHNESS |
Ra 0,8 |
Ra 0,2 |
/ MATERIALS AND HARDNESS
| Dimensional Tolerances | Estandard | Precision |
|---|---|---|
|
THICKNESS |
+ / - 0,1 |
+ / - 0,005 |
|
LENGTH |
+ / - 1 |
+ / - 0,1 |
/ MATERIALS
Steel used in the production of Slide-Ways, is generally part of the family of “Tool Steels”. This family of steels include only high al-loyed steels. Their chemical composition is specifically thought, in order to allow for heating treatments to be applied, and enhance the steel properties.
The Slide-Ways made by Zorrotz are done with selected steels in order to guarantee:
- Low friction resistance
- High wear resistance.
- Long life of the Slide-Way.
- Rolling elements resistance.
- Surface hardness.
/ HEATING TREATMENT AND HARDNESS
The hardness is one of the most important characteristics of a Slide-Way. A higher hardness is generally synonymous of a good wear resistance and, in turn, longer durability over the time.
By carrying out different heat treatments, it is possible to act on the hardness of the steels used for the manufacture of the slides and, therefore, to increase their useful life.
The usual heating treatments offered by Zorrotz are:
Through Hardening:
- The part is fully heated and tempered down to the “core” of the piece.
- The Slide-Way will have the same hardness all over.
- Allows achieving very high resistance to compression.
- Not suitable for extremely thick slideways.
Induction tempering: Surface treatment
- The hardness on the piece reaches a maximum depth of 3-4 mm
Nitriding: Depth of hardness limited to 1 mm.
- The thickness of the hardened layer is less than that obtained by induction hardening.
- Hardness can reach 1000 Vickers (Depending on the steel used).
| Heating Treatment | DIN | Werkstoff | Hardness | Hardness Depth | Hardness at the Core | Max Length |
|---|---|---|---|---|---|---|
|
THROUGH HARDENING |
90MnCrV8 |
1,2842 |
Up to 60/62 Hrc |
|
|
3,8 Mt |
|
X160CrVMo12 |
1,2379 |
Up to 60/62 Hrc |
|
|
3,8 Mt |
|
|
X210CrVMo12 |
1,2080 |
Up to 60/62 Hrc |
|
|
3,8 Mt |
|
|
TEMPERING INDUCTION |
C60 |
|
Up to 60/62 Hrc |
Up to 3mm |
|
4 Mt |
|
C45 |
|
Up to 58/60 Hrc |
Up to 3mm |
|
4 Mt |
|
|
40CrMnMo7 |
1,2311 |
Up to 58/60 Hrc |
Up to 3mm |
100 Kg/mm2 |
4 Mt |
|
|
40CrMnMoS 8.6 |
1,2311 |
Up to 58/60 Hrc |
Up to 3mm |
100 Kg/mm2 |
4 Mt |
|
|
X48CrMoV 8-1-1 |
1,7225 |
Up to 58/60 Hrc |
Up to 3mm |
100 Kg/mm2 |
4 Mt |
|
|
90MnCrV8 |
1,2842 |
Up to 58/60 Hrc |
Up to 3mm |
|
4 Mt |
|
|
NITRIDING |
VARIOUS |
|
Up to 1000 V |
0,1mm -> 1mm |
MULTIPLE |
7 Mt |