Questions about thread technology

Spindles are manufactured in the following materials

For the production of our threaded spindles, we use almost all materials available on the market, such as free-cutting steels, heat-treatable steels, heat-resistant, low-temperature and high-temperature-resistant steels, rust- and acid-resistant steels, heat-resistant nickel alloys, non-magnetizable steels, duplex and super-duplex steels, aluminum, Brass, copper, titanium and titanium alloys and even plastics.

Materials for movement threads
11SMn30 – 1.0715
C15 – 1.0401 or 1.1141
C35 – 1.0501
C45 – 1.0403 or 1.0503
42CrMo4 – 1.7227
V2A – e.g. 1.4301, 1.4021, 1.4104, 1.4057
V4A – e.g. 1.4401, 1.4404
V5A – 1.4571
titanium
Aluminum – EN 6082
Brass – Ms58, Ms60
Special materials – titanium, inconel

Materials for fastening threads
11SMn30 – 1.0715
St37 / S235 – 1.0037
St 50-2 – 1.0050
S355 – 1.0045
41Cr4 – 1.73035
30CrNiMo8 – 1.6580
34CrNiMo6 – 1.6582
42CrMo4 – 1.7227
24CrMo5 – 1.7258
21CrMoV5-7 – / 1.7709
40CrMoV4-7 – 1.7711
X22CrMoV12-1 – 1.4923
X19CrMoVNbN11-1 – 1.4913
NiCr20TiAl – 2.4952
V1A – 1.4305
V2A – e.g. 1.4301, 1.4021, 1.4104, 1.4057
V4A – e.g. 1.4401, 1.4404
V5A – 1.4571
titanium
Aluminum – EN 6082
Brass – Ms58, Ms60
Special materials – titanium, inconel

With thread grinding, materials with strengths higher than 12.9 can also be processed.

Nuts are manufactured in the following materials

For the production of our threaded nuts we use almost all materials available on the market, such as free-cutting steels, heat-treatable steels, rust and acid-resistant steels, plastics, aluminum, titanium and titanium alloys.

Maintenance-free materials are a special area of nut materials. In addition to aluminum-bronze, red and gray cast iron, brass and copper, plastic with optimized sliding properties are used in particular.

Standard materials are included

Materials:
11SMn30 – 1.0715
C45 – 1.0403 or 1.0503
Rg7 – 2.1090
Rg5 – 2.1096
GBZ12 – 2.1052
Aluminum bronze – 2.0936
GG25 – 0.6025
PAN bronze – various alloys
42CrMo4 – 1.7227
V1A – 1.4305
V2A – e.g. 1.4301, 1.4021, 1.4104, 1.4057
V4A – e.g. 1.4401, 1.4404
V5A – 1.4571
titanium
Aluminum – EN 6082
Brass – Ms58, Ms60
Plastics – POM, PA, PA6, PA66, PEEK, PET, HD-PE, PVC, PE, PTFE, PBT, PPS and PVDF Slip-optimized plastics PA6 MoS2, PA66 / PTFE, PA 6 / SI, POM / PTFE, PET-GL , PTFE / glass, PTFE / carbon, PEEK / GL and HD-PE / PTFE
Compounds with brand names – iglidur, Zedex, Nylatron, Ertalyte etc.
Special materials – titanium, inconel

When using injection-molded plastic threaded nuts, we have the option of developing application-specific special compounds from a quantity of 25KG.

Threaded nuts must be secured against turning or axial displacement.

The torsion and axial locking is usually provided by the design, for example by fastening on the flange, axial or radial bores or by a form fit (for example a wrench surface). In the case of metallic threaded nuts and low torques, it is also conceivable to glue in threaded nuts; in the case of higher torques, nuts can also be welded.

With flange nuts made of plastic, the maximum tightening torque (2.5 Nm) of the fastening screws must be taken into account. Metallic press-fit sleeves are ideally used to achieve higher tightening torques. The use of liquid screw locking agents has also become established (for example Loctite 270 or Loctite 243).

In certain applications, the use of axially split threaded nuts may also be necessary or useful.

Before assembly, the nut should be lubricated if the material combination and the application require it.

When pulling the threaded nut onto the spindle, make sure that the spindle is cleanly deburred. A hand bevel makes assembly easier.

Ball screw nuts are usually supplied on an assembly sleeve. With KGT nuts, it is essential to ensure that the nut is not simply pulled from the spindle or assembly sleeve, as otherwise balls could fall out and the nut can no longer absorb the maximum forces.

junaspin is happy to help with the assembly and selection of your threaded nuts. Contact us.

In order to be able to integrate threaded spindles in the application, a tenon machining is usually required. Alternatively, spindles can also be used Clamp rings for small loads, storage can be carried out using Plain bearings can also be done directly on the thread.

In order to be able to cleanly connect bearings, drive wheels, clamping sets, couplings, etc. to the spindle, there are the following machining options:

  • Cylindrical fits
  • Surfaces (clamping surface, flat, D-cut, square, hexagon)
  • Chamfers
  • Recesses and grooves for retaining rings
  • Axial and radial bores
  • cone
  • Axial and radial threads inside
  • External axial thread
  • Keyways
  • Gears
  • Pressing on, shrinking on and gluing on bushings and sleeves

All common machining methods are available for the production of these tenons, such as turning, milling, grinding, drilling, cutting, sawing, separating, pressing, eroding, honing, polishing, countersinking and slotting.

junaspin produces spindles ready for installation, according to customer drawings or to match the spindle bearings offered. If you are not sure which processing is useful or necessary for your application, please contact us.

junaspin efficiency

The efficiency describes the relationship between the output and the input power. As a rule, the highest possible degree of efficiency, i.e. a low loss of power, is aimed for.

The efficiency is determined by the thread profile (thread type), the pitch (flank angle), the load and the coefficient of friction (i.e. the sliding pair).

In order to achieve the highest possible degree of efficiency, attention should be paid to the details when selecting the dimensions and thread profiles. By optimizing the sliding pairing and choosing the right lubricant, the efficiency of existing screw drives can also be increased.

The efficiency can usually be documented via the current consumption of the motor.

The efficiencies vary greatly. These are between 15% (single-start, unlubricated sliding thread) up to 99% (optimized ball screw drives)

Junaspin is happy to help with the design. Thousands of test results are documented in our database. In addition to the pure calculation, experience from “real applications” and tests can also be incorporated.

The importance of good lubrication is more well known today than ever. Experts estimate the annual follow-up costs due to insufficient lubrication in German mechanical engineering at high three-digit million sums.

Lubricants help to reduce friction and wear. A positive side effect of the lubricating properties is that the drive requires less energy and the efficiency is significantly improved.

When selecting a lubricant, the required temperature range must be taken into account. The material compatibility must also be taken into account. Not every lubricant is compatible with plastics and therefore also suitable for sliding screw nuts made of plastics (such as POM, PEEK, PA6.6 and other sliding-modified plastics).

The adhesive force of the lubricant on the spindle must be taken into account. Otherwise there is a risk that the lubricant will be “thrown off” at high speeds.

Industry and application-specific requirements must also be taken into account, for example FDA approval in the area of food and pharmaceutical applications or PWIS-free in the area of applications in painting technology.

In some applications, a lubricant can also be used to preserve or protect the spindle from rust.

That junagrease spindle grease was specially developed for the lubrication of screw drives (especially ball screws, trapezoidal threads and high helix threads). But “the lubricant partner you trust” can also give you appropriate recommendations.

Depending on the application, however, it may also be necessary for a screw drive to run absolutely dry. The offer of special materials for the Dry run designed is growing steadily. The development of modern sliding-modified plastics (also called triboplastics) should be mentioned here, but also of various high-performance bronzes. With these materials, dry lubricants (e.g. PTFE, MoS2, silicone, graphite, etc.) are embedded in the material.

junaspin is happy to help with the design. Hundreds of test results for various lubricants are documented in our database. In addition to the pure calculation, experience from “real applications” and tests can also be incorporated.

Theoretically, threaded spindles can be manufactured in any length. The standard program is limited by the raw materials available on the market. The material length here is usually 6 meters.

The maximum spindle length that can be used is also limited by the application itself. The Deflection and also the permissible buckling force must be taken into account.

If spindles are required which are longer than 6 meters, there are various ways of producing them. Usually an extra forging blank has to be made in excess length. This is associated with corresponding delivery times and costs.

But there is also the possibility of putting together overlong threaded spindles from 2 or 3 parts. The connection of the two rods takes place before the thread is applied. We have special concepts for this connection that also take into account the drive torques occurring in the application.

junaspin is happy to support you in the selection and design of your screw drive. We would be happy to create your personal concept for how your oversized spindle can be manufactured.

In order to be able to define the usability of a screw drive, the p * v value (pv value) is decisive. Frictional heat arises mainly when high loads (p) are combined with high speed (v). If only one of the two values is very high, the applicability is less limited.

The use of a sliding pair with the lowest possible coefficient of friction naturally fundamentally reduces the pv value. Choosing the right one Lubricant significantly helps to minimize friction and increase the maximum permissible pv value.

In addition to the frictional heat that can be derived from the application, many other factors are relevant for the maximum permissible pv value, for example the duty cycle, the ambient temperature, the stroke length and the heat dissipation values of the materials used.

These many factors are evaluated in the calculation using correction factors so that, for example, with very short switch-on times, the pv value can be exceeded very significantly for a short time.

In the case of short switch-on times, the maximum permissible pv value can be provided with a correction factor.

For duty cycles of less than 10% and appropriate lubrication, we recommend not to exceed the pv value of 0.6.

However, it is imperative to note:
In addition to the maximum permissible pv value, wear must be considered separately in each case.

junaspin is happy to support you in the selection and design of your screw drive. We are happy to provide the max. Calculate the permissible PV value of your screw drive for you, taking into account the service life. In addition to the calculation, we can also incorporate experience from “real applications” and tests.

Of course, threaded rods made of steel can also rust from the influence of moisture and chemicals. But contact corrosion, vibration corrosion, surface corrosion and crevice corrosion cannot be ruled out with threaded spindles made of steel.

If there are problems with the formation of corrosion, initial lubrication is often sufficient to preserve the spindle. When choosing one Spindle fat Care should be taken to ensure that the grease is reversible and washable.

Should the lubrication not be sufficient too Coatings be a sensible alternative to stainless steels. Electro-galvanizing, hot-dip galvanizing, chrome-plating, phosphating, burnishing, bonding, thick-film passivation, nitro-carburizing, anodizing, anodizing and painting are particularly suitable for screw drives. The suitability of the coating in terms of wear resistance and coefficient of sliding friction must be checked separately.

If the use of surface coatings is not sufficient to achieve a suitable corrosion protection class, the only option is to use stainless steels (Inox, VA steel, Nirosta). However, not all stainless steels are equally suitable for thread rolling. In addition to the yield point, there are a few other parameters to consider.

Titanium, bronze and aluminum can also solve problems with regard to corrosion.

junaspin can have almost all coatings applied by external partners.

In addition to the question of manufacturability, we also have experience with the application and durability of various alloys and surface processes. In addition to the pure calculation, experience from “real applications” and tests can also be incorporated.

Every now and then screw drives are used in mobile devices, e.g. in wheel alignment devices, automobiles, stair climbers or medical devices. Weight plays a major role in these applications.

The reduction in weight can be significantly influenced by the choice of materials, for example by using plastic nuts in combination with aluminum spindles.

In some cases, the use of a safety nut / catch nut can also optimize the diameter of the screw drive because the safety factor can be reduced.

There is also the option of subsequently drilling the spindle hollow or rolling the thread onto a pipe.

junaspin will be happy to support you in the selection and design of your screw drive. We are happy to calculate the remaining strength after the weight has been “optimized”. In addition to the technical requirements, economic aspects are of course also relevant here. We can incorporate relevant experience from “real applications” here.