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Chosing the right heat shrink tubing product

Choosing the Right Heat Shrink Tubing Product for the Job

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Step 1: Understand Your Application

The most important aspect of choosing the right heat shrink tubing product for your needs is to understand and define all that is necessary for your application. The only way to ensure that you’re getting the most appropriate and cost-effective product is to fully understand your application and the requirements that you need to meet.

Sizing Requirements

Regardless of whether you’re using heat shrink tubing in an electrical application, as a strain relief, as a protective covering, or for any other reason, determining the correct size is the most important factor.

A great start point is to measure the 2 most important dimensions:

  1. The largest diameter that the expanded sleeve needs to slide over
  2. The smallest diameter that the tubing needs to completely cover to (after shrinking).



These two dimensions will be used later in Step 2 to help you determine the required size and shrink ratio for your tubing.

Another important dimension to consider is the wall thickness. A certain minimum wall thickness might be required due to the electrical requirements of your application. Or, if the tubing is going to be subjected to excessive abrasion or wear, you may wish to have a heavier wall thickness than the standard size offers. In addition to defining your required minimum wall thickness, it is also necessary to determine the diameter at which this wall thickness will be required. This information is critical in choosing the required tubing size in Step 2.

Electrical Property Requirements

If your heat shrink tubing is going to provide electrical insulation or bundle electrical wires, it is likely that it needs to meet certain regulatory guidelines. In order to choose the correct product for your application, you’ll need to know if any specifications need to be met.  In the heat shrink world, the most common ones are listed below

  1. UL (Underwriters Laboratories)
  2. CSA (Canadian Standards Association)
  3. ASTM (American Society for Testing and Materials)
  4. AMS (Aerospace Material Specification)
  5. EU (European Union)
  6. RoHS (Restriction of Hazardous Substances Directive)
  7. VDE (Verband der Elektrotechnik)

There are literally hundreds of industry or application based specs that you may need to consider,  automotive or military specifications are very common and can differ greatly from one manufacturer to another, but regardless of the origin, these specifications all tend to be in place to cover common electrical requirements such as dielectric strength and flame resistance.

Other possible electrical requirements could be that the tubing must be free of halogens or that it must be made out of a specific material. Make sure you understand all of the electrical requirements before you choose your heat shrink product.

Operating Environment

Another critical step in defining the requirements of your heat shrink tubing application is to understand the environment in which the tubing will operate. For example:

  • Will the tubing be subjected to excessive abrasion or flexing?
  • Will the tubing come into contact with any oils, greases, fuels, chemicals, or other fluids?
  • Will be used indoors or outdoors?
    • If it is going to be used outdoors it could be subjected to excessive UV exposure.
    • If it is going to be lying on or buried below the ground, it may need to have superior resistance to fungus growth.
  • Does the application require an enhanced environmental seal (as obtained with adhesive-lined heat shrink tubing)?
  • Will the tubing need to protect any sensitive portion of the object the tubing is covering?

All of these factors and more will need to be considered prior to selecting your heat shrink product.

Step 2: Determine the Required Tubing Size

The next step is to determine the most appropriate tubing size for your application. Using the measurements you obtained in Step 1, you’ll need to define the following tubing dimensions that best suit your needs:

  • Minimum expanded ID
  • Maximum recovered ID
  • Minimum recovered wall thickness.

This section will explain each of these tubing dimensions and how they relate to your application measurements found in Step 1.

Expanded and Recovered Inside Diameters

Heat shrink tubing is traditionally specified by the minimum original inside (“expanded”) diameter and the nominal shrink ratio.  However, a good heat shrink product datasheet will not only list the minimum expanded ID and nominal shrink ratio of the tubing, but also its maximum recovered ID.

First, check that the minimum expanded ID of the tubing is greater than the largest diameter that the sleeve needs to slide over (using the measurement you made in Step 1).  Then, check that the maximum recovered ID of the tubing is less than the smallest diameter that needs to be completely covered (also measured in Step 1).

The diagram below illustrates these tubing dimensions:

Heat Shrink Tubing before and After Recovery

Shrink Ratio

If the product datasheet does not have maximum recovered ID listed, you can estimate it using the minimum expanded ID and the shrink ratio.

Example 1
If a heat shrink product has a 2:1 shrink ratio and the minimum expanded ID is 6.4mm, then the maximum recovered ID should be 3.2mm

6.4mm ÷ 2 = 3.2mm.

Example 2
If a heat shrink product has a 3:1 shrink ratio and the minimum expanded ID is 39.0mm, then the maximum recovered ID should be 13.0mm

39.0mm ÷ 3 = 13.0mm.

Wall Thickness

Now that you have determined the required expanded and recovered ID’s (and also the shrink ratio), you may need to consider the wall thickness required for your application.

The wall thickness of a heat shrink product is traditionally specified as the minimum thickness at the fully recovered stage. If the diameter of what you are covering is greater than the maximum fully recovered diameter of the tubing, the final wall thickness will be less than what is specified on the datasheet.  This is illustrated below:

Recovered Heat Shrink Tubing

The dimension trec is the wall thickness of the tubing when allowed to shrink fully without restraint. However, since your object is restraining the tubing from shrinking fully, you’ll need to determine the required tact before you can specify the tubing. The approximate relationship between the two thickness dimensions is as follows:

rec = (d obj  x  t act) ÷ d rec

or

act = (d rec  x  t  rec) ÷ d obj

Variable Key
act = actual wall thickness after shrinking onto the underlying object
obj = diameter of the underlying object
rec = specified recovered wall thickness of tubing
rec = specified recovered diameter of the tubing

Length & Longitudinal Shrinkage

If tubing length is a critical dimension for your application, longitudinal shrinkage must be considered. In addition to shrinking in diameter, most heat shrink tubing products will also shrink in length.  This is particularly important when using cut pieces or you have a specific length that you need to cover.

The amount of long shrink you can expect depends largely upon the shrink ratio and the manufacturing processing variables, but it is generally about 5%-10% of the original length.

Step 3: Choose the Appropriate Heat Shrink Material

So, you now understand your application and have chosen the appropriate size tubing.  You are now ready to choose your heat shrink material. Often there are multiple products that will meet your needs, so it is important to also know the cost and availability of each option. This section will examine how to choose the right

Often there are multiple products that will meet your needs, so it is important to also know the cost and availability of each option. This section will examine how to choose the right material.

Polyolefin is the most widely used material for manufacturing heat shrink tubing, but there are many other speciality heat shrink tubings available in various fluoropolymers and elastomeric materials along with commercial options such as PVC.

Within each of these material families, there are many different compounds that have been designed to excel in certain environments and/or meet particular specifications.

Polyolefin Heat Shrink Tubings

Polyolefin is used widely as the base material for standard heat shrink tubing products, when this material is combined with other compounds, it is possible to produce bespoke materials that  perform in certain ways:

  • LTF100-V – Low-cost heat shrink tubing
  • LT100 – Low shrink temperature tubing
  • PLF100  –  Military Grade heat shrink
  • PLZH100  –  Zero Halogen heat shrink
  • PLF103 – 3:1 High shrink ratio tubing
  • SEC150 – Transparent Flame retardant

Adhesive-Lined Heat Shrink Tubings

Adhesive lined (or “dual wall”) polyolefin heat shrink tubing is a speciality product that has a wide variety of uses. This product is simply a standard polyolefin tube that has an inner-liner of adhesive that melts and flows at the same temperature at which the polyolefin tubing shrinks.

As heat is applied and the tubing is shrinking, the flowing adhesive fills voids and conforms to the underlying shape. This forms an environmental seal, protecting the underlying component(s) from moisture or other contaminants. An example of the use of adhesive-lined tubing is shown in the photo below:

Adhesive Lined Heat Shrink Tubing

Other Heat Shrink Materials

In addition to the products mentioned above, there are also other specialty heat shrink products available.  These products all offer unique qualities such as extreme temperature resistance, exceptional chemical/fluid compatibility, and/or superior mechanical properties.  Among theses products are:

Due to the enhanced qualities of these products, they are generally more costly than Polyolefin tubings. In some cases, the price differences are extreme. The diagram below gives you a simple, generic comparison of the price differences for a sampling of heat shrink materials:

Step 4: How to Use Heat Shrink Tubing

For a full, in depth explanation of how to install heat shrink tubing, please read the article below, it discusses various heating methods commonly used to shrink heat shrink tubing. It will also provide some handy tips:

How to Install Heat Shrink Tubing
How to Install Heat Shrink

Crosslinking Cross-linking

What is heat shrink tubing crosslinking ?

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The Raychem Corporation pioneered the development of heat shrinkable products back in the 1960’s.  Raychem developed new types of plastics and elastomeric materials that were engineered to possess unique properties.  This was achieved by modifying the raw material using radiation technology – a process that is now known as crosslinking (or cross-linking, x-linking).

The original crosslinking process worked by bombarding the raw material of the plastics with high energy electron beam radiation.  The radiation caused the long chains of polymers to link together, altering the chemical structure of the material and increasing the molecular mass.   Although the materials are usually crosslinked through the use of electron beams, it can also be achieved chemically using butperoxides, or moisture.

The process for making heat-shrink tubing is as follows:

  1. The raw material is chosen based on its properties. The material is often compounded with other additives (such as colorants, stabilizers, etc.) depending on the application. A starting tube is extruded from the raw material.
  2. The extruded tube is then taken to a separate process where it is cross-linked, usually through radiation. The cross-linking creates a memory in the tube.
  3. The tube is heated to just above the polymer’s crystalline melting point and expanded in diameter, often by placing it in a vacuum chamber.  Whilst in this expanded state it is rapidly cooled.
  4. Later, when heated (above the crystalline melting point of the material) by the end user, the tubing shrinks back to its original extruded size.

As previously mentioned many of the material properties can be improved by crosslinking, for example:

  • Mechanical properties, such as tensile strength
  • Scratch resistance
  • Performance at higher temperatures, often with an increase in the melting temperature
  • Resistance to chemicals because of lowered solubility in organic solvents
  • Gas permeation reduction
  • Shape memory retention. Certain plasyic types (elastomers etc) may be crosslinked to a slight degree to give them “memory” – they will return to their original shape after being expanded.

Typical advantages of crosslinked materials include:

The most commonly used product categories for these enhanced wonder plastics are Single Wall Tubing’s, Raychem’s RNF-100 and RNF-3000 being the quality standard bearer.

Dual Wall Tubing’s with ATUM, HTAT and SCL leading the way in this category, and Elastomeric Tubing’s with RW-200 and DR-25 key products to the aerospace and defence markets.

This technology was originally developed in the 1950’s since then these basic product categories have been refined, enhanced and developed. Careful synthesis of materials provided products which could perform selective and very specific purposes. The addition of adhesives, shielding facilities, fibre and fabric materials ensures that the products are capable of performing in the most sophisticated installations.

Typical uses include:

PMG Company are uniquely placed, we can offer all the Single and Dual Wall products manufactured by Raychem/TE Connectivity either supplied TE Branded or where commercial constraints are paramount PMG can offer our own Plastronic brand equivalent:

Cross reference guide

Can I cross refer heat shrink tubing part descriptions?

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Many people ask us to cross refer heat shrink tubing part numbers.  If you have a description from another supplier or manufacturer and you would like to cross-refer this to a PMG Company product then please contact us.

If you already now the product description, then the table below gives a quick and easy cross reference guide:

Cross refer heat shrink tubing part numbers and product families

PMG Company Raychem
/Tyco
DSG-Canusa Hellerman  Sumitomo 3M LG
LTF100 CGPT DERAY H F2 (2) GSHS-1625G
PLF100 RNF-100 DERAY I TF21 B2 FP 301 GSHS-1635F
PLF103 RNF-3000 CPX-300 TF31 B2 (3X) SFTW-203 GSHS-3635
PLF100 GYS DCPT CPX201 GYS GSHS-635Y/G
PLDW100 ATUM DERAY IAKT EPS W3B2 EPS 300 GSHS-3635W
PLDW104 ATUM CPA 100 W3B2 EPS 300 GSHS-4635WT
PLK175 RW-175 / KYNAR DERAY KY175 TK20 K KYNAR GSHS-1675
PLDR100 DR-25 DERAY V25 PST-M LD-DRET
PLM100(A) MWTM CFM LG-PMWT
PLT100(A) WCSM
PLV200 RW-200 / VITON DERAY VT220 VITON E FR3 VTN 200 GSHS-1650F
LTF100-V VERSAFIT CPX876 F2 (2)
TFE-250 TFE DERAY PTFE TFE TFE
PLZH100 ZH-100 C2T200 TR27 NH
PPS VERSALEX
PPS-FR VERSALEX-FR
PLCE100(A) SSC CCAP-FR/RL SKE
PMG Company Alpha FiniSHRINK Shrintek Hilltop Cableorganser  
LTF100 FIT 221-2 C SP HSP1 HS2
PLF100 FIT 221 CM SP HSP2
PLF103 FIT 321V CMX3 SP3X HSP3
PLF100 GYS FIT 260 CYG SP
PLDW100 FIT 321 CDW3X SPDW DWA HS3E
PLDW104 FIT 321 CDW4X SPDW DWA HS4A
PLK175 FIT 350 CK SK HKY HSKY2
PLDR100 SHDR SE 150 HDR HSDR
PLM100(A)   MA        
PLT100(A)            
PLV200 FIT 650 SV VITON
LTF100-V FIT 221 TW C SP HILVERS
TFE-250 FIT 500 SPTFE STFE HPTF HSPTFE
PLZH100 SHF ZH-100
PPS HILLFLEX
PPS-FR
PLCE100(A) MEC End Caps

For more information on how to cross refer heat shrink tubing part numbers, please contact using the form below:

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Heat shrink colours

What colours are heat shrink tubings available in?

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Heat shrink colours – What colours are heat shrink tubings available in?

When it comes to heat shrink colours, many people ask us the same question, “what colours are heat shrink tubing products available in?”.  The answer is in fact quite complicated as the products are available in a wide range of colours; some standard and some that are specialist or bespoke.

The first thing to know is that that within the electronics industry, the standard colours are internationally recognised as follows:

Standard Colour Abreviation Electronics market Colour Code
BLACK BLK 0
BROWN BRN 1
RED RED 2
PINK PNK 2L
ORANGE ORN 3
YELLOW YLW 4
GREEN/YELLOW STRIPE
(EARTH)
GYS 45
GREEN GRN 5
BLUE BLU 6
VIOLET VLT 7
GREY GRY 8
WHITE WHT 9
CLEAR/TRANSPARENT CLR X

The heat shrink colours listed in the table above will differ and are not controlled or standardised by a Ral colour chart or similar colour scale, so between manufacturers (or even different batches of the same manufacturers material), it is not uncommon to find slight colour variation.

When it comes to bespoke colours, many applications now call for the heat shrink tubing to be supplied to a specific RAL colour (or another industry standard colour code), these are available but usually, have to be manufactured specifically to meet the individual requirement.  This is generally not a problem but the following considerations must always be made:

  1.  It is likely the MOQ (minimum order quantity) will be greatly increased.
  2. The price is likely to be much higher than normal.
  3. A significant lead time is likely to be imposed.

For our full range of heat shrink tubing products, please click here.

If you have a requirement for a bespoke colour or you just want some more information, please contact us using the form below:

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How to Install Heat Shrink

How do I install heat shrink tubing products?

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How do I install heat shrink tubing products?

There are many ways to install heat shrink tubing, but the most common way is to use a hot air gun.  The instructions below will explain how to do this.Before installation, it is extremely important to ensure that you have chosen the correct size of the product.  When selecting the correct size tubing, you must consider the 80/20 rule – the chosen size should allow a minimum shrinkage of 20% and a maximum of 80%

Step 1

Apply the heat shrink over the substrate and heat evenly around the tube, working either from the middle out or from one end to the other. Gradually heat the product ensuring that no air is trapped under the tubing until full recovery is achieved.

Step 2

Heat shrink tubing will also shrink in length (longitudinally) so as the tubing shrinks in diameter it is likely it will also shrink in length.

Step 3

Typically the longitudinal shrinkage is no more than 10%, although different products will have different tolerances.  You must always take longitudinal shrinkage into consideration, especially when cutting the tube to length.

Step 4

It is possible to minimise the longitudinal shrink by recovering the product at either end first and then working towards the centre.  However, when doing this, care needs to be taken to avoid trapping air in the sleeve as this may restrict the product from recovering fully.

Step 5

Alternately, if your application calls for the tubing to be more critically applied at a certain point (at one end for example), start the shrinking process in the critical area and work away, towards the other end.

Step 6

If the substrate onto which you are applying the heat shrink tubing is made of metal or any other heat conductive material, take the time and care to ensure that that the object is pre-heated to avoid cold spots.  These cold spots can counteract the heating process and cause the tubing to recover irregularly.

It may also be worth noting:

When preparing the heat shrink tubing for installation, it is essential that care is taken to ensure that any ends are cut and trimmed smoothly.  Jagged or poorly cut edges can cause the tubing to split during installation.

Each product has a recommended optimum shrink temperatures that should be considered when setting the temperature of the heat gun.

During the shrinking process, you should always ensure that the workplace is well ventilated.

watch this video to see the process

To buy heat shrink tubing from our on-line shop, please visit the Heat Shrink Tubing Section

Heat Shrink and Braid Cut Lengths

Can You Supply Your Products In Cut Lengths?

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Can you supply your products in cut lengths?

Here at PMG Company we have our own in-house cutting shop that enables us to supply cut lengths on the vast majority of our various tubings and sleevings.  These products can be cut to almost any length you require and we can control the cutting very closely allowing for tight tolerances to be adhered to.

Customer requirements are becoming ever more complex and it’s clear that additional support is required.  That’s why PMG Company took the decision to set up a range of additional services, key to the list is the cutting shop.  It give you, our customers the flexibility you require.

If you need a braided or a heat shrinkable sleeving product in cut lengths or supplied cut to a specific tolerance, then look no further. Our ‘in house’ cutting shop is equipped with a range of specialised cutting machines including:

  • Hot knife cutters – for cutting braid and prevent fraying.
  • Standard vertical blade cutters – for accurate and clean heat shrink sleeve cutting
  • Tolerance cutters – for tight cut length tolerances, as well as controlled angle of the cut.
  • High volume commercial – used for high quantity runs

As a standard offering, our cut length service is available in bags of 100 pieces, 250 pieces, 500 pieces and 1000 pieces as standard.   Obviously, for bulk enquiries or small batch runs, we are happy to help and the numbers can be customised where needed.

For more information on our cutting services, please click here.

For all your cut length requirements please contact us using the form below:

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Pre Printing Services

Can You Print On Heat Shrink Tubing?

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Printing – Can You Print On Heat Shrink Tubing?

We have our own on-site and fully equipped printing facility that enables us to print on our full range of heat shrink tubing and identification products.

The complexity of electrical systems is increasing and the need to identify wires and cables is becoming more important. With this in mind, we set up a facility to provide bespoke services for customer printing and identification requirements.

Ranging from simple prints on continuous tubes (with or without scoring to allow the product to be torn and applied) through to individually printed and sequences pieces, our print shop can provide you with a made to measure solution.

Many customers simply require printing onto standard (and stocked) heat shrink tubing products. This provides a convenient and inexpensive additional service (there is a small fee). Options include:

  • Text
  • Serial numbers
  • Logos
  • Graphics
  • Continuous lengths
  • Cut pieces

As well as printing on standard heat shrink sleeves, we can also provide our full range of identification products pre-printed to your request.

With over 30 years of market knowledge and experience, we can also provide advice and expertise to help you choose the right solution:

  • Which materials to use
  • Print performance
  • Application advice

For more information on our printing services, please click here.

For all your printing requirements please contact us using the form below:

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