Many firms display banners which say … “ISO Certified”; what exactly does that mean?How have computers changed the spring industry?
How do I choose the most appropriate spring material for my spring design?
Is it necessary to specify helix direction on spring blueprints?
What is the correct way to get an accurate coil count in a spring?
Q.
Many firms display banners which say … “ISO Certified”;
what exactly does that mean?
A.
ISO refers to a universal worldwide quality program for managing and documenting
a company’s business system. It is not dimensional quality control
although certain aspects of the program such as measuring instrument calibration
attempt to insure the integrity of the end product. Other elements of
the program include a documented employee training system and customer
order review to be sure the vendor understands exactly the product the
buyer is specifying.
A qualified third party auditor must review a firm's comprehensive ISO system every six to nine months in order to maintain the ISO certificate. Imperial Spring Company (Milldale, CT) is ISO 9002 registered since 1997, as well as QS 9000 registered, which means this firm is approved by the automotive industry within the ISO system.
Q.
How have computers changed the spring industry?
A.
Computers have changed every aspect of our industry from spring design
to office management but the greatest impact is in the manufacturing process.
Computer controlled equipment is more precise, easier and faster to set-up
and adjust. Such equipment is able to deliver mechanical motions which
used to be impossible or required sophisticated custom engineering. Imperial
Spring has a variety of CNC (Computer Numerically Controlled) equipment
used to manufacture and measure our product.
Q.
How do I choose the most appropriate
spring material for my spring design?
A.
A variety of questions must be asked and answered to arrive at the best
spring material including:
- The atmosphere in which the product operates
- The frequency of cycles and the amount of deflection
- The cost of the spring or wireform in relation to the
overall project
- The expected life of the product
Some springs are used in products that are discarded in a relatively short time frame and have a low cycle frequency during that time. In those cases the design should specify a general purpose spring wire, which can keep costs down while not affecting product performance.
Conversely stainless steel is often specified in products frequently exposed to moisture. Other spring materials include Hastalloy C-276 alloy (for use in highly corrosive atmospheres), music wire (which is a carbon steel and has the best resiliency to being deflected and distorted), chrome silicon, copper, aluminum, phosphorous bronze and the list goes on.
Q.
Is it possible to obtain a small quantity
of a product to check my spring design prior to placing a large production
order?
A.
In a word, yes, however it’s imperative we both understand exactly
what we are attempting to accomplish. All of our products are custom manufactured
and often the cost to set up equipment and ensure the quality to produce
prototypes is little or no different than set-up costs to run a production
order; for example if the prototypes require zinc plating the cost for
sub contracting may be exactly the same for 10 pieces as for 2,000. However,
if spring load is the only concern of the design, prototypes can be evaluated
without being plated. We have equipment and methods specifically geared
for prototypes and short run production and regularly produce orders for
as few as one or two pieces.
Q.
Is it necessary to specify helix direction
on spring blueprints?
A.
Generally, compression springs have an optional helix direction but in
special applications such as clutches or drapery hardware the helix may
be vital. Torsion springs and extension springs with open hooks are also
critical applications where helix specification is mandatory for either
assembly, function, or both. It’s always best to present a drawing
with the correct helix and end configuration shown as well as the correct
written terminology to reinforce the drawing. Refer to the drawing (below)
which clarifies left hand helix and right hand helix and avoid terminology
such as clockwise and counter-clockwise. Please note, double torsion springs
always have one side left hand and one side right hand.
Q.
What is the correct way to get an accurate
coil count in a spring?
A.
Coils are full 360 degree circles; however, springs often are designed
to have not (for example) exactly five coils or exactly eight coils but,
rather, four and one-half coils or eight and one-quarter coils. Please
refer to the sketch (below).
Q.
Do you stock catalogue springs?
A.
No, but on medium to large quantities our prices are competitive with
stock spring warehouses.
Q.
Can you help with my spring design?
A.
We work with customers all the time, often making suggestions seeking
to improve their design and the fit or function of the part. We may also
suggest changing the design in order to facilitate assembly or reduce
the cost of production.
