Infrared splicing isn't the same as hot
splicing, but both joining techniques offer advantages. Which splicing
technique is right for your custom rubber gaskets - and how do these film
splicing methods compare to cold bonding?
Splicing joins
lengths of extruded rubber to create elastomeric products such as hollow
O-rings, low-closure force seals, and large-diameter profiles that are too
expensive to mold. Splicing methods
vary, and choices include film splicing, cold bonding, C-press injection
molding, and vulcanizing. By working with an experienced gasket fabricator, you
can select the right splicing technique for your application.
Each splicing method
offers advantages, but film splicing creates strong bonds without adhesives. This
joining method also supports fast cycle times and creates strong corners that
won't crack. Film splicing isn't new, but it's important to understand how
infrared splicing compares to traditional hot splicing. For larger seals, more
durable splices, and an alternative to molded parts, IR splicing is a strong
choice.
How Hot Splicing Works
Hot splicing uses
heat, pressure, and polyethylene film to join lengths of EPDM, SBR, NBR, TPE,
silicone, and other rubber materials. Special presses call film splicers are
available in single-unit stations and in carousel or line configurations. The plastic
film is fed manually or released from a dispenser. With multi-unit splicing
lines, the film dispenser may travel between presses
With traditional
hot splicing equipment, a heated clamp holds the plastic film and the rubber
part or parts in place. Endless seals such as O-rings can be created by joining
the ends of a single length of rubber cord. Custom fabricators can also produce
four-corner spliced picture frame gaskets (bezel gaskets) from rubber profiles
with 45° miter cuts. Hot splicing also supports 90° joins in rubber parts like this bulb
seal.
Hot Splicing and Cold Bonding
Hot splicing is
fast and efficient, but traditional production techniques can pose challenges. After
clamping the rubber and starting the heater, an operator must wait for the
plastic film to cure. Multi-unit lines let operators move onto subsequent
splicing units, however, and promote overall efficiency. Yet there are other factors
that cause some gasket buyers to choose a joining method such as cold bonding
instead.
When hot splicing
occurs after taping, it's important to cool the splicer's clamping mold to
protect the tape's pressure-sensitive adhesive (PSA). Reciprocating water
coolers work well, but cooling jackets can add tooling costs. Cold bonding doesn't
add these expenses and is great for angled parts; however, cold bonding is best-suited
for seals that won't be exposed to high temperatures or outdoor environments.
Advantages of Infrared Splicing
Infrared
splicing helps to solve these film splicing challenges. Instead of heating the metal
clamping molds, an infrared splicer uses IR light to heat the entire surface.
This light-based heating technique uses less energy than traditional heaters, and
creates strong bonds in the flash of a lightbulb. Importantly, IR splicing also
supports precise part alignments without degrading PSA tapes or film liners.
Unlike cold
bonding, infrared splicing also eliminates time-consuming, manual operations
that can introduce inconsistencies. Advantages of IR splicing include press
clamping range, too. Molds that are three times wider allow gasket fabricators
to make 3 to 4 splices at a time instead of just 1 or 2. Plus, it's easier to
hold down large, complex shapes with infrared splicing.
How to Splice Rubber Gaskets
Ten years ago, Elasto Proxy acquired a
multi-unit film splicer that opened up new production possibilities. More
recently, we've acquired a single-unit infrared film splicer with
state-of-the-art capabilities. Different splicing methods offer different
advantages, but which splicing technique is right for your application? For
answers to all of your questions about spliced rubber gaskets, ask Elasto Proxy.
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