loading

Search   Machined Spring (overview)

x
SPECIALIST PRODUCTS

Machined Spring (overview)

ABSSAC Lead Screws, Ball Screws, and Shaft Couplings
Call: 01386 421 005
Email: sales@abssac.co.uk
Web: www.abssac.co.uk

The Unique Machined Spring

  • Machined from a single piece of material
  • Predictable spring rates
  • Your choice of end attachment
  • Multi functional capability
  • Choice of material
  • Double and triple start spring configurations

ABSSAC Lead Screws, Ball Screws, and Shaft Couplings

Compression Springs

Torsion Springs

RELEASE THE POTENTIAL OF THE UNIQUE MACHINED SPRING

“It is better to entertain an idea than to take it home to live with you for the rest of your life” Randall Jarrell 1914 -65

The machined spring product available from Abssac Limited is a formidable package. For those engineers familiar with the traditional wound spring format we are offering a new way of looking at both performance and attachment.

Do you know what a machined spring is?

Whilst we all agree that traditional wire wound springs have numerous bonafide applications, the very nature of how they are manufactured can limit their reliability and performance in the more demanding or high duty cycle spring applications. Machined springs, as many of our existing costomers have found, are more useful than you may first think!

Designs are limited only by your imagination

As with its wire wound brother, all types of spring format such as, compression, extension, torsion, lateral translation and lateral bending springs are available in the machined format. However, from this point the similarities between wound and machined springs stop. Machined springs can provide very precise, linear deflection rates because virtually

all residual stresses are eliminated. As a result, there are no internal stresses to overcome before deflection occurs, which can be the case in the wire wound spring. In addition to this we can offer multiple start spring coil configurations.

The most common configuration is the single start, which consists of a

single continuous coil element, which starts at one end and terminates at the other end, much like its wire wound counterpart. However, we can uniquely offer a double start or indeed triple start spring which has two or three intertwined continuous coil elements.

Repeatability - Reliability

With the machined spring, perpendicularity, parallelism,
lateral bending, axial and torsional rates can be
GUARANTEED.

Machined springs

Tel: +44 (0)1386 421005 • Fax: +44 (0)1386 422441
sales@abssac.co.uk • www.abssac.co.uk

ABSSAC Lead Screws, Ball Screws, and Shaft Couplings

Precision Elasticity

The advantages of Multiple start spring elements are beneficial because they not only provide redundant elastic elements should a failure occur, but a failed element (coil) will be physically trapped by the remaining one and in many cases will allow the albeit reduced function of the spring design to still operate.

Another multi-start benefit applies to compression and tension springs, as when compressed (or extended), single start springs provide a reaction force plus a moment. On multiple start flexures, all internal moments are resolved within the spring itself, which translates into excellent compression or extension parallelism.

There is no tendency for the spring to squirm when deflected, and no restraint is necessary to resolve the free moment. Double and triple start variants make the loading points irrelevant on the radius of the spring but increase the accuracy of parallelism.

Integration of multi parts

Machined springs multi parts

The Challenge

The Solution

1 part

3 parts

Once the working dynamics of the spring are calculated and agreed we can then look at the method of attachment. In many cases the machined spring incorporates other parts of the working mechanism into the single part, such as flanges, gears, splines etc, making the final item more reliable. If you require more detailed information on the above product, such as physical dimensions, performance data or just to see the full range of products available, please feel free to contact one of our technical sales engineers who will be more than happy to help you.

The 6 possible Cartesian co-ordinates of a spring

Machined springs cartesian co-ordinatesWhen considering the dynamics of the machined spring we look at the 6 possible Cartesian co-ordinates, those being X,Y,Z and then the rotation ROTX, ROTY & ROTZ. A wound spring tries to deliver all 6 axis potentials when it is asked to move.

A machined spring can be a single degree of freedom system, delivering motion in only one of the possible six axis and the double start machined spring is the closest single Cartesian co-ordinate deflection part available with todays technology.

  • UX, motion on the x axis (associated with lateral translation)
  • UY, motion on the y axis (associated with lateral translation)
  • UZ, motion on the z axis (associated with compression and extension)
  • ROTX, rotation about x axis (associated with lateral bending)
  • ROTY, rotation about y axis (associated with lateral bending)
  • ROTZ, rotation about z axis (associated with torsional rotation)

Tel: +44 (0)1386 421005 • Fax: +44 (0)1386 422441
sales@abssac.co.uk • www.abssac.co.uk

ABSSAC Lead Screws, Ball Screws, and Shaft Couplings

Example Markets

Medical Research and Development Aerospace

Motorsports Communications Aerospace (space)

Finite Element Analysis
FEA Analysis machined spring
Machined Spring

FEA analysis is used

Finite Element Analysis (FEA) is employed to verify the feasibility and performance of the machined spring. For example, the stress in compression and extension machined springs is dominantly torsional shear, where as the stress in torsional machined springs is dominantly pure bending stress.

The advantages of the machined spring product are numerous having proven itself in medical, aerospace, semiconductor and motorsport industries to name a few.

Where ever a wound spring is not able to meet your performance criteria or a new spring design requires ultimate accuracy and repeatability, the machined spring is the ideal partner.

Tel: +44 (0)1386 421005 • Fax: +44 (0)1386 422441
sales@abssac.co.uk • www.abssac.co.uk

ABSSAC Lead Screws, Ball Screws, and Shaft Couplings

Wound Springs - the basics

Wound Springs
  • Only single coil spring configurations available
  • Non predictable linear rates
  • Variable spring rates in batched quantities
  • Parts have to be ground to ensure accurate internal and external tolerances
  • Accurate mixtures of Cartesian spring rates are not available
  • Has residual stress effecting performance
  • Special or custom end attachments have to attached to the wound spring after manufacture
  • Limited material utilization
  • Less reliability & performance to the system
  • Variable parallelism and perpendicularity during use

Machined Springs - the advantages

  • Single, double and triple coil start spring versions
  • Predictable linear rates are available to meet application requirements 100% repeatable rates (up to 1% on rate)
  • Each part is supplied to meet exact customer size and performance requirement
  • Dimensional variances are typically much smaller in machined springs
  • Can be configured to your compression, extension, torsion, lateral translation, lateral bending rate - or a mixture of predetermined rates
  • Can have virtually no residual stresses in final part
  • Special or custom end attachments can incorporated into the one piece design
  • No need for multiple suppliers
  • Variety of materials including titanium, stainless steels, high strength steels and engineering plastics can be utilized
  • Unbeatable parallelism and perpendicularity delivering reliability and performance to the system
Machined Springs

Tel: +44 (0)1386 421005 • Fax: +44 (0)1386 422441
sales@abssac.co.uk • www.abssac.co.uk

ABSSAC Lead Screws, Ball Screws, and Shaft Couplings

Application Examples

The Challenge

The Challenge

6 part wound torsion spring assembly incorporating two separate wound springs.

The Solution

The Solution

Replaced by a single part machined torsion spring, with double start flexures and integral flanges.

The Challenge 2

The Challenge

12 part wound compression spring assembly stage.

The Solution 2

The Solution

Replaced by a single part compression spring, with both a left and right hand flexure eliminating torsional movement during compression.

Four part wound compression spring assembly.

The Challenge 3

The Challenge

The Solution 3

The Solution

Replaced by a single part machined compression spring.

Spring Configurations

Spring

Double Start

Triple Start

Single start machined springs can satisfy most applications but in some cases we also consider double start or indeed triple spring configurations which have two or three intertwined continuous coil elements, still within the same single part construction. In effect, this puts multiple independent helixes in the same cylindrical plane, which provides totally enhanced spring performance. With the machined spring, perpendicularity, parallelism, lateral bending, axial and torsional rates can be guaranteed.

We like to think of it as.... PRECISION ELASTICITY.

Multi-start springs have many advantages. When applied to compression and extension springs, a single start spring provides a reaction force plus a moment. On multiple start flexures, all internal moments are resolved within the spring itself, which translates into excellent compression or extension parallelism.

BS EN ISO9001 : 2000

ISO 9001
Established in 1982 Abssac is a EN ISO9001:2000 approved company.
First article inspection reports to AS9102 on request.

Tel: +44 (0)1386 421005 • Fax: +44 (0)1386 422441
sales@abssac.co.uk • www.abssac.co.uk

ABSSAC Lead Screws, Ball Screws, and Shaft Couplings
Abssac product range

ISO 9001FSC paperCall: 01386 421005
Email: sales@abssac.co.uk

Abssac Limited
E1A The Enterprise Centre, Enterprise Way
Evesham, Worcestershire, WR11 1GS

Tel:
+44 (0)1386 421005
Fax:
+44 (0)1386 422441
Email:
sales@abssac.co.uk
Web:
www.abssac.co.uk
ABSSAC Lead Screws, Ball Screws, and Shaft Couplings