always wanted to know about
How to avoid Running a Risk in Fusing
Garment manufacturing cannot be imagined without fusing these days. Fusing could therefore be expected to have become a matured technology by now. Nevertheless, it has become an increasing issue lately: Changes in the material, in quality expectations and textile care methods entail more and more unpleasant problems, which are often realized after an entire batch of defective pieces has been produced. What counts is to minimize the risk in fusing - a real challenge.
- Modern fashion fabrics and interlinings are more delicate.
- Fabrics are generally finer and lighter.
- They are more sensible to temperature and pressure.
- They have more tendency to shrinkage under temperature.
- Many fabrics are elastic, some in both directions.
- Textile finish with softeners can effect fusing.
- Modern fusible interlinings are lighter and thinner.
- There is more chance of strike back of resins.
- For a soft hand the resin quantity should be at minimum.
However, fusing should be perfect:
- with no damage to the fabric,
- without deformation,
- with sufficient bond strength,
- also in day-to-day practice,
- also in foreign production,
- every day,
- productive and cost effective.
The fusing equipment must be perfect:
- controlled heat and pressure application according to the material
- by a precise and effective heating system,
- by a sensitive and exact pressure system,
- by a material friendly transport system,
- reliability and safe operation,
- by a strong machine design,
- by safe function of all machine components,
- by easy maintenance and service,
- by using the correct working width,
- by sufficient machine capacity,
- by well designed work stations,
- by loading aids for soft fabrics,
- by modular stackers.
What is Fusing Temperature ?
Fusing in fact is lamination of two ore more textile surfaces by using thermoplastic resins. Therefore temperature is the most important (but also the most critical !) factor for the application of fusing. In the day-to-day practice there are generally two kind of „temperature“ mentioned:
1. the temperature suggestion of the interlining supplier,
2. the temperature setting or reading on the fusing machine.
The fusing result is very much depending on the question whether or not the set values are indeed at exactly the points where they should be. A fusing machine has different temperature levels:
To secure sufficient bond strength a certain minimum glue line temperature is needed, whereas for avoiding of fabric damages the surface temperature of the belts should be as low as possible.
This contradictory requirements must by all means be considered in the design of modern fusing equipment, particularly in view of the increasing number of delicate fabrics. For the proper selection of fusing machine settings it is important to know that the temperature development in the glue line depends very much on the weight of the fabric to be fused, and that the temperature curve can vary drastically, as shown in the following graph:
A good harmony in the design of heating elements, heating zones, temperature control, temperature contact, belt and pressure system is crucial for an optimal glue line temperature situation, particularly when fusing fabrics with varying weight. Decisive is here the contact between fusing material and heating surface by the interaction of heat zone curvature and belt tension:
Another important design condition: The system temperature, which is the temperature at the hottest spot on the actual electric heat source, should be as low as possible for the following reasons:
- to avoid overheating of the material,
- to avoid belt damages when the power brakes down,
- to reduce energy cost,
- to minimize temperature radiation,
- to avoid cooling down times when switching off the machine,
- to avoid temperature variations.
The best heating system does not make sense when the temperature control system is poorly designed. Its functions must be fast and precise. At any time the temperature on the belt surface must correspond with the reading of the temperature regulator. There may not be any temperature swing, regardless of the degree of loading the machine with material. A slow reacting control system leads to unacceptable temperature variations, whereas a fast reacting system keeps the fusing temperature on a constantly even level, as shown in the graph.
Slow temperature control systems require a setting at the lowest point, in order to avoid underfusing - with the disadvantage, however, that the unavoidable temperature peaks lead to overfusing, shrinkage and resin strike back.
How to check temperature and heating system of a fusing machine?
- Most suitable for a temperature test are the well-known paper measuring tapes.
- The measured temperature between the belts (without fusing material) at medium machine speed should be in accordance with the temperature reading on the thermostat.
- In case of a separate digital temperature reading it should, after heating-up of the machine, indicate exactly the temperature setting.
- The easiest way to test the glueline temperature is also by using the paper tapes.
- To test the capacity and the reliability of a heating system one should prepare a number of swatches of heavier fabric and interlining with temperature tapes in-between, pass them through the machine successively and compare the results: All tapes should show the same temperature.
The heating capacity and the geometry of the heating zones are decisive for the application of a fusing machine in view of the material to be fused:
In this case heating form both top and bottom side with separate control is advisable to guarantee the correct temperature balance.
- Lighter material like for shirts, blouses or dresses require generally lower heating capacity or shorter heating zones.
- In this case the main heat should come through the face fabric side, in order to have the melting resins flow towards the face fabric.
- If primarily heavier fabrics are to be fused, or in case of sandwich or multi-layer fusing, higher heating capacity and a longer heating zone is needed to make sure that the machine capacity can follow the loading speed of the operators.
1. Heating Profiles: with specially treated surface and optimum curvature for best belt contact
2. Heating Mat: intimately laminated to the inside of the profile for best heat transfer
3. Sensor Position: ideally next to heating mat and belt contact surface for quick reaction
4. Contact Surface: continuous contact with the belts for continuous heat flow
5 .Profile Thickness: relatively thin for fast heat transfer to the belt surfaces
6. Curved Heating Zones: for intensive contact between material and heating surface by high fusing belt tension
7. Separate Heating Zones for optimum adjustment of the temperature balance according to fusing method.
The Pressure System
Whilst the intimate contact in the heating zone is important for the temperature built-up and the resin flow in the material, a precisely controlled pressure in the pressure system as well as an exact adjustment of the specific pressure and a mild pressure application are crucial for an optimum anchoring of the resins in the fiber structure of the fabric.
There are basically two different pressure systems available:
1. The standard pressure system
It consists of two pressure rollers, of which at least one is coated with silicone, to absorb minor differences of thickness within the material or between the material layers.
Normally the pressure is applied by the force of pneumatic cylinders onto one of the two pressure rollers, whereas the other roller is fixed to the machine frame. The specific pressure between the rollers is variable by adjustment of the air pressure.
Because of its limited elasticity the silicon coating can only absorb thickness variations within limitations. In other words: Simultaneous fusing of different material weights can lead to bond strength problems on the lighter material. In addition: Varying coverage of the machine working width can also result in varying bond strength because of the different distribution of the total pressure force depending on the width of the parts when passing the rollers.
Therefore a standard pressure system is primarily suitable for fusing of light fabrics like for shirts and blouses. When fusing heavier material on a standard pressure system one must consider the degree of belt coverage for an accurate adjustment.
2. The FLEXO pressure system
In the FLEXO system one of the two rollers is designed as an air-filled flexible hose. The internal air pressure of the FLEXO roller is precisely adjustable to the required specific fusing pressure, which is perfectly even distributed over the complete working width of the machine, regardless of material thickness or belt coverage.
Due to the air cushion effect the pressure is applied to the material much milder compared to standard systems. The advantage is less flattening and less shine.
As a result the FLEXO pressure system is suitable for all different fabrics with important extra features for production flexibility and fabric friendly high quality fusing.
Specific Pressure and Pressure Evenness
Contrary to flat bed presses, it is almost impossible on continuous fusing machines, to determine the exact pressure applied to the material to be fused, except for those with flexo pressure system. The specific pressure is not only depending on the pressure reading on the pressure dial, but also from a few additional factors, such as:
- hardness, thickness and surface of the silicone coating,
- thickness and hardness of the material to be fused,
- degree of machine width coverage.
Therefore when fusing with a machine equipped with a conventional pressure system the pressure adjustment must be decided after fusing tests with the specific material. A swatch of a standard part width should be used for finding out the optimum settings, considering the best possible bond strength, surface and handle results.
Additionally it is advisable to tests the evenness of the pressure over the working width of the fusing machine. After testing the evenness of temperature one should load the machine over the working width with several samples of the same material combination and check the bond strength of all samples. in case they are not even it is necessary to check the pressure roller coating for delaminations, partial hardening or other surface changes, which could easily be caused by aggressive belt cleaning chemicals.
Flexibility by different Pressure Systems
The possibility to choose between three different pressure systems: the normal pressure system, the double pressure system and the FLEXO pressure system offers all varieties for today’s modern fabrics.
Even after years the pressure system is interchangeable in case of need, i.e. the production has changed.
So, your fusing machine can be always updated to your latest production.
Flexibility in Pressure made by KANNEGIESSER
Single Pressure System "C"
* all kind of ordinary fabrics
* outerwear mainly
* reliable and sturdy
Double Pressure System "CU"
* special treated fabrics
* dress and casual shirts
* flexible pressure range
* for all kind of interlining
Flexo Pressure System "CF"
* for sensitive fabrics
* balancing thick and thin fabric
* soft pressure supply
* for single and sandwich fusing at the same time
* sadwich fusing
* thick and thin shell fabric at the same time
*high quality fusing for outerwear
The Conveyor System
The conveyor belts are the most delicate design elements of a continuous fusing machine. Their function, however, is crucial for the performance of all other elements. Therefore they have to meet with high expectations:
- They must be strong, with high tear and tensile strength.
- The surface must be smooth, to avoid marks or structure transfer on delicate fabrics.
- The surface should not allow any resin adherence.
- They must withstand temperatures up to 250 ° Celsius.
- They must be thin for optimum heat transfer.
- They may not change their dimensions when heated up.
- They must have a smooth teflon coating.
- To avoid shifting of material they must have an antistatic treatment.
- To avoid marks they should not have a thick welding joint.
- The belt edges must be sealed, to avoid fraying.
It goes without saying that not only the belts but also the other design elements of the transport system of a fusing machine must offer the required precision and reliability:
- The speed of both belts must be perfectly synchronized.
- The tracking control system must be very sensible.
- Variations of the belt tension must be compensated automatically.
- The belt tension should be relatively high and precisely adjustable, in order to assure an even and intensive contact.
- Belt changes should be easy and fast. There should be no belt welding on or in the machine.
- Belt cleaning devices should be available according to the particular use of the fusing machine.
1. Cover Belt: - endless high tech fabric
- smooth surface
- Teflon coating
2. Tracking Sensor: - for sensible belt tracking control - no damages of belt edges
3. Control Roller: - gentle horizontal movement
- no overstreching of belts
4. Safety Sensor: - for additional safety
- stops machine if belt goes off
5. Belt Tensioning: - for uniform belt tension
- for intensive heat contact
6. Tensioning Roller: - for compensation of belt tension
- for centered belt tracking
7. Transport Belt: - endless high tech fabric
- smooth surface
- Teflon coating
Organization and Productivity
Depending on labor cost and productivity requirements the economy of a fusing division can be just as important as the securing of quality.
The economy of fusing is determined by quite a few factors:
- bundle size,
- bundle preparation,
- matching of interlining bundles,
- cutting precision, particularly of interlinings,
- fusing method (single, sandwich or block fusing),
- distribution of operations to the operators,
- work place engineering (shelves for fabric and interlining bundles),
- work aids (tape shooters etc.),
- degree of training and experience of operators,
- lane configuration and lane width,
- length of loading area,
- Input batch conveyor feeding station,
- matching of loading times and machine speed,
- safety of machine functions (exit side!),
- unloading and stacking of fused parts,
- work flow to following operations.
The capacity depends on material, quantity and variations of fabrics and interlinings to be fused. The exact capacity can only be calculated according to the individual situation of the particular production.
Data Bank for Fusing uses as basis a time table of the different handling operations in connection with fusing. This time modules are the major part of the Capacity Calculations which are available for all different kinds of garments like jackets, overcoats, shirts etc.
The individual capacity calculation considers:
- all fabric and interlining parts,
- the fusing method,
- planned or actual production figures,
- daily working time or shift time in minutes,
- the individual efficiency,
- the individual cost per minute.
Well organized loading systems as well as modular stackers are excellent supplements to a fusing machine. The individual components can be:
- input batch conveyor,
- workplace engineering,
- lay-up stacker,
Input Batch Conveyor:
- for better work flow and shorter through-put times,
- for improved loading capacity: The parts are moved automatically and at high speed into the fusing machine.
- for loading of instable and elastic material without deformation.
- The length of the active loading belt is adjustable to the part length.
- Available for one or two lanes, two lanes can be combined.
Work Place Engineering:
- modular system for individual design,
- catalog of different shelves for different part sizes,
- single or multiple racks,
- inclination for easier part handling,
- universal stand.
lateral loading table return-feed system tape un-winding and re-
with shelve winding device
Modular Stacker Systems:
* universal lay-up stacker, model AST, for all part shapes and sizes.
Service and Maintenance
In order to make sure that a fusing machine works problem-free, it is vital to take care for regular maintenance and service including checking of all major functions. A nice side effect can in most cases be a cost reduction. This relates particularly to the conveyor belts. These are made of a rather delicate material and should therefore be on the first place of the maintenance list:
The Ten Golden Rules of Belt Care
1. Interlinings should not overlap:
They soil the conveyor belt.
(And it is waist of material !)
2. Temperatures set too high cause
resin strike back and soiling
of the cover belt.
3. During the breaks the belts should
regularly be cleaned from dust
and dirt with the cleaning flag.
4. Cleaning agents should be used carefully,
in order to avoid build-up on belt
inside, rollers or heating elements.
5. Never use aggressive chemicals or sharp
tools for cleaning: This shortens the
6. Covers or towels of cleaning bars or
cleaning devices should regularly be
checked and replaced.
7. Transfer and strip-off blades should
be cleaned in regular intervals from
resin and dust build-up.
8. The machine must be cleaned before
shut-down: Resins hardened over night
cut the belts when started in the morning.
9. Tracking and Tension of the belts should
regularly be checked and readjusted, if
10. Scissors should be tied up with a string:
Fused scissors are not in fashion.
Systematic maintenance ensures constant trouble-free function of a fusing machine. This, however, requires some checks and control operations by the machine operators or the maintenance personnel which ideally should follow clearly defined and listed rules.
In order to make a systematic maintenance easier we generally equip all fusing machines with a so-called Maintenance Guide Sheet, placed in a little box on the side panel of each machine. (To often not used !)
The idea is to have listed on one page all daily, weekly and monthly maintenance functions which should be confirmed and signed by the responsible people.
Control and Securing of Fusing Quality
Since fusing is a crucial process in garment manufacturing, it is not completely without risk. For this reason it is necessary to follow, aside from regular maintenance, a few important rules to secure fusing quality:
1. For each fabric the most suitable interlining should be selected, possibly under the assistance of the interlining supplier.
2. New fabrics should be pre-tested, including dry-cleaning or wash test, to find out the optimum fusing conditions.
3. The fusing equipment must daily be checked for the basic functions, particularly for temperature accuracy.
4. The pressure system must daily be checked by fusing several samples over the working width and testing the evenness of bond strength.
5. The test results should be recorded in a journal, in order to check back if later on fusing problems come up.
A well designed fusing system – properly used and regularly maintained – together with a good concept of quality control are the keys to reduce the risk and the cost of fusing to a minimum !
Quite many factories have only one fusing machine available. In these cases the complete production is definitely depending on this bottle neck machine. Therefore the safe functions of the fusing equipment must be guaranteed.
For this reason only those products should be considered for which in case of break-down a manufacturer trained service is available within reasonable time !
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We are at your disposal to supply you spare parts for VEIT - Kannegiesser and of course appropriate custom made size fusing belts