Stenter machine can be defined as a stente finishing process in which the open width form of the fabric is treated to set up the required width, weight, and fabric texture as per customer’s specification. These requirements from the customer are achieved by a single Stenter machine process (i.e. Chemical application, Overfeeding-Compaction, Drying- Curing and setting of Width and Yield).
Stenter Machine Process Requirements
Equipment used
Following equipment is used for Stenter Finishing process
Bruckner stenter machine
Key Accessories
Following equipment is used for Stenter Finishing process :
pH papers,
Buckets,
Sewing machine,
Measuring balance,
Measuring tape,
Scissors, and
Materials / Chemicals Used
The materials and chemicals used in the stenter machine process for TC fabric, 100% Cotton fabric, CVC fabric and for Water Repellent fabric are described below.
Types of Fabric
Materials/Chemicals Used
TC Fabric
Softener
Additive
Stiffener
Acetic acid to adjust the pH
100 % Cotton Fabric (soft)
Softener
Additive
Acetic acid to adjust the pH
100% Cotton Fabric (anti shrinking)
Softener
Additive
Resin
Catalyst
Wetting agent (when chemical absorbency is poor)
Acetic acid to adjust the pH
CVC Fabric (medium touch)
Softener
Additive
Stiffener
Acetic acid to adjust the pH
CVC Fabric (soft)
Softener
Additive
Acetic acid to adjust the pH
Water Repellent Fabric
Hydrophobic agent
Stiffening agent
Softener
Additive
Acetic acid to adjust the pH.
Safety
Following Do’s and Don’ts are to be followed during operation:
Do not wear loose dress that may entangle with the machine parts while running.
Always wear rubber shoes.
Never touch the uncurling roller while running the machine.
Be careful in manual pinning of fabric.
Do not insert hands between the rollers during running the machine.
Wear an eye goggle and hand gloves during preparation of chemical solution.
Do not touch the padder during operation.
Be careful about the selvage cutting blade.
Be familiar about volatile chemicals.
Be careful in handling the trolley of fabrics.
Be aware of the first aid treatment procedure.
Operation Procedure of Stente Machine
Operation Staff for stente machine
Operation stuffs of Finishing Process includes:
Manager
Textile Technologist / Production Executive
Production Co-ordinator
Operator
Assistant Operator for stente machine
Checklist Before Production
Operator must check the following items before finishing, re-finishing, heat setting and stretching process in Stenter machine process:
Machine parameters are set according to program.
Required manpower is available for feed side and delivery side.
Required chemicals are available.
Batch for Feed side is set.
Lead cloth is guided up through passage point to operator station.
Operation Procedure for 100% Cotton Fabric (Soft Finish)
Calculation of Solution Amount
Production officer or shift in-charge will provide the recipe with the process flow. The finishing procedure begins with the calculation of solution amount for a particular batch. The formula is as follows :
Solution Amount = Total Weight of Fabric ´ Pick-up Percentage (%) + Trough Content + 3% Wastage.
Suppose, we have 500 kgs of fabric, which are to be finished, and for that we need to prepare the solution.
(where 80% is the average pick up of knit fabric, and 50 litre is the trough content of machine trough).
Operation Procedure
Chemicals are measured using the electronic balance and taken in buckets separately. Chemicals are diluted with hot or normal water based on the references of the chemical literature provided by the chemical company.
Mixing tank is filled up with 50% of water to the required solution level and then chemicals are poured separately into the tank through a piece of filter cloth. Then water is added to get the target solution.
Chemicals are stirred for five to seven minutes by the electrical mixer impeller in the mixing tank and then send to the machine through. Then operator will run 1-meter fabric as a trial run to check the parameter(s), softness and hardness, shade match, etc. which is required by the customer. A small piece of fabric from that trial portion is given to the shift in-charge to check the parameter(s).
If the trial fabric matches with the customer-approved sample then production officer decides to go for the bulk production and operators starts the machine for production.
For the bulk production chemicals solution is prepared using the formula mentioned above and poured into the chemical trough.
The capacity of each tank is 400 litre.
Product Quality Check
Shade Check: During the processing of bulk production of any batch, operator checks the shade in the Stenter machine process. If any deviation is detected he informs the responsible shift officer who takes the necessary action to overcome the problem. If the officer fails to rectify the problem he informs the department head who finally gives the decision.
Fault Check in Stenter Machine Process: The operator checks for Knitting faults (i.e. double yarn, yarn contamination, fly yarn, etc.), Spinning faults (i.e. thick & thin yarn, barre mark, etc.) and other faults (i.e. dye resist mark, band line, chemicals spots, torn and hole, variation of shade, fabric structure, etc.) during the process.
In case minor faults occur within the half rolls of fabric (while running about 20-25 rolls of fabric) which is not resulted from previous process and also not recorded on the batch card the necessary action(s) to be taken is as follows :
Check the feed side to make sure that these faults didn’t occur from the previous process.
Stop the machine to identify whether these faults are occurring due to machine faults (i.e. from padder, chain bar, air duct, etc.) or the faults are due to the chemicals (check cleanliness, setting of machine parameter(s) and chemical composition).
If any spot on the fabric, which is not resulted from the previous process, is detected during processing, it indicates that the sequence of chemical pouring in the mixing tank is not correct which resulted in bad chemical reaction. If this happens, the process should be immediately stopped and responsible officer should be informed for investigation.
Width Check in Stenter Machine Process: Measure fabric width by using a measuring tape and compare it with the required width that is mentioned by production officer on the batch card or program.
Design, Fabric Bow and Slant Check in Stenter Machine Process: Check the design, bowing and slanting of fabric at the delivery side. Adjust the machine by straightening the courses line of the fabric for checking the bowing and slanting.
Pin Setting Check in Stenter Machine Process: Check at the delivery side whether the selvage of fabric is detached from pin and for minimum of 0.5″ each side pinning wastage is maintained, if any abnormality found, immediately inform the head operator.
Q.C. Sample Tests
1-meter sample is cut from each batch during processing and are sent to the Q.C. Department for lab testing. In Q.C laboratory, these samples are tested according to the quality requirement of the customer such as dimensional stability test, washing fastness, water fastness, light fastness, pilling test, crocking (dry & wet) etc.
After all necessary testing, the results are recorded on the Q.C. Sheet. Refer to Off Line QC Test Specification (Document No. 81-101) for details.
Applicable Forms & Documents
Forms & Documents Used
The necessary forms & documents for finishing process are listed below :
Process Batch Card
Daily Finishing Production Report
Machine Downtime Report
Recipe Sheet
Identification Sticker
Program Register of Stenter Machine
Production Register of Stenter Machine
Document Flow
The document flow of Finishing Process is as follows :
Operator fills out the Batch Card and the concerned officer put his signature on it upon verification. The Batch Card moves with the fabric for the next step of finishing process(e.g. Tubular Compactor, De-water, Drying or Slitting).
The Daily Finishing Production Report is prepared to show shift wise daily production of finishing section of BK. Production officer prepares it and sign on it. The department head, Finishing verifies the facts and figures and put his signature on it. Finishing department records this report for future reference.
Machine Downtime Report is maintained to keep record of any stoppage in production due to machine break down or any other reason. Operator fills this and the responsible officer sign on it upon verification
Recipe Sheet is used to give recipe for a particular machine in each shift. It is also termed as the Chemical Consumption Report. Responsible officer prepares it and the Department Head, Finishing verifies and signs on it.
Identification Sticker is attached with every fabric roll that includes the Order number, Customer, Batch/Roll number, Quality, Colour/Shade, usable width and composition. This helps the stores personnel to easily store and locate a particular roll of fabric at Finished Goods Stores.
Program Register of Stenter Machine is maintained against Recipe Sheet to keep track of the production progress of a particular batch.
Production Register of Stenter Machine process is used to keep records of date wise production details. Operator fills this out along with his remarks (if any) and this report is recorded for future reference.Attachments: Examples of all applicable forms and documents are attached. Know more it
Textile stenter machine parts are very important to complete the whole stente process. The steps process using stenter frame and relax dryer and compactor. The damp fabric runs through the relax dryer (no pins) at a fast speed because the fabric has only 30% water content. Fabric comes out dry at 68-70″. The Maintenance Department performs the preventive maintenance task as per the schedule. Refer to Maintenance Specification for details.
Stenter Frame
Stenter frame – 5 chamber (could be more or less but settings below would change) run at 230-260 degrees fahrenheit (normally running at 330-350 degrees f) 45-50 yards/min. The knit fabric is dyed in tubular form, then slit. The fabric goes into the stenter frame wet at 60-63″. The fabric is put on pins and needs to be stretched by 10-15 inches. This means that the wet fabric is put on the pins and then opened up by 10-15 inches into the stenter frame. If the fabric is not pulled open enough, it will not get the torque out of the fabric. Very important: fabric should exit stenter frame with 30% water – still damp
Run at 280-300 degree fahrenheit (normally running at 350 degrees f)
45-50 yards/min
**test**before the compactor, the fabric can be tested for torque and shrinkage to see if there are any problems. We test for torque by making 3 boxes across the fabric to see what the average is (see attached picture). This test is important. The torque at this point should be very low, under 3%. If it is not, the fabric wasn’t pulled open enough on entry to the shrink dryer or there is a knitting issue. **the length shrinkage should be 6-7% at this point. If length shrinkage is higher than this, the fabric wasn’t pulled open enough. If length shrinkage is greater than 6-7%, the compactor won’t be able to achieve the target shrinkage of 4×4% (5×5 is the specification). Very important: the fabric should be off-grain (not be strait) coming out of the stenter.
Compactor
The fabric then goes to the open width compactor. The fabric should be run natural through the compactor do not try to make the grain strait. The finished fabric should be off grain by about 8 inches out of the compator. The temperature on the compaction machine needs to be 104-115c (220-240 f) to create enough heat. Fabric is then rolled up.
Textile Stenter Machine Set-up
Machine set up for the Stenter machine is described below:
Machine Parameters
Set-up Value
Padder Pressure
2 to 8 bar (depends on the pick up requirement of the fabric.)
Temperature setting
(90-180)0C (according to the shade, quality and process of fabric.)
Blower fan setting
Low or high (according to the quality of fabric.)
Exhaust fan setting
Manual
Width of Textile Stenter Machine chain setting
110 cm up to 260 cm (according to the required width of fabric.)
Overfeed
0%-60% (as per the required weight of fabric.)
Burner gas pressure
30-50 m/bar
Machine speed
6 up to 60 m/m (according to the quality of the fabric.)
Light weight (100-140) gm/m2
20-30 m/m.
Medium weight (150-180) gm/m2
14-18 m/m.
Heavy weight (190-250) gm/m2
10-15 m/m.
Response to Equipment Faults
Following are the response to be taken in case of equipment fault during Stenter machine process:
Textile Stenter Machine Faults
Response
Pinning shoe problem
Mechanical Engineer should be called
Pinning brush problem
Mechanical Engineer should be called
Electrical sensor selvedge problem
Electrical Engineer should be called
Chain stops
Electrical Engineer should be called
J-box compensator problem
Electrical Engineer should be called
Chain width disturbance
Mechanical/Electrical Engineer should be called
Burner, blower, motor problem
Mechanical/Electrical Engineer should be called
Padder, plaiter problem
Mechanical/Electrical Engineer should be called
Machine /Area Cleaning
The daily and weekly cleaning works for Stenter Machine are described below :
Clean the padder & rollers after complete every batch (when the next shade is different from the previous shade)
Clean the sieves that can be reached from outside of the Textile Stenter Machine a minimum of once per shift.
Clean the entire screen filter in every shift.
Clean all the air ducts at least once a week.
Clean the chemical mixing tank once a week.
Clean all the buckets after every preparation of chemicals.
Stenter machine is electrical machines used in textile industry for stretching or stentering thin fabrics such as muslin. Stenter electrical machines are called as stenter hook. In stenter open compactor fabrics enter. Here Cotton fabric shrinks widthwise & weft are distorted due to bletching & dyeing process.
Functions of Machinery and Equipment:
Spirility measured by the stenter m/c
It works as textile machinery and equipment
Stenter m/c control shrinkage property
Stenter mc is used for curing treatment for resin, water repellent fabric
Heat setting is controled by the stenter for lycra fabric, synthetic and blended fabric.
Fabric inlet: Fabric after mercerizing, after dyeing even some time after bleaching & peach come to stenter for different application. Fabric roll is feed into inlet of stenter machine which passes over few rollers & guider to come in chemical tank.
Fabric inlet
Chemical mixing tank: Chemical is mixed according to required for processing in the machine. Few typical recipes are shown below:
A typical recipe for soft finish: Fabric construction: 88×38/10×10, oxford
Sapamine cws: 12 gm/lt
Argafix t-8 : 12 gm/lt
iii. Acetic acid: 1 gm/lt
Temperature: 60 – 70 ‘C
Fabric speed: 50 m/min
A typical recipe for water repellent finish: Fabric construction: 116×52/16×16, Twill
Ultra gaurad 600 : 20 gm/lt
Phobal RHP: 60 gm/lt
iii. Phobal XAN: 10 gm/lt
Paraset VA : 15 gm/lt
Appriton EM: 40 gm/lt
Acetic acid: 1.0 gm/lt
vii temperature: 150 – 160’C
vii. Fabric speed: 60 m/min
A typical recipe for Teflon finish: i. Olephobal CO – 70 gm/lt
Phobal RHP _ 10 gm/lt
iii. Hydrophobal XAN – 6 gm/lt
Acetic acid _ 1 gm/lt
Temperature _ 170-180°C
Speed – 30 m/min
Chemical tank: Here according to finish required from the mixing tank chemical comes to bath for padding. Here there is three bowl padding system followed by squeezing. Pressure is around 2.5 to 3 bar.
Skewing & bowing control unit (bianco): In this unit both bowing & skewing is controlled by means of mechanical application. Here there are two types of roller. The bend roller is called bowing roller & the number of bowing roller is 3. That can move upward & downward direction. When the bowing is in downward direction then the roller moves upward to control it. There are also three parallel rollers which is called skewing roller. The amount of skew allowable is settled in the control panel. According to this the roller moved forward & backward to control skewing. If left side is moves forward in the fabric then in skewing roller moves backward to control this. This bowing & skewing is measured by sensor which is shown in the panel board. It is done in the entry level.
bowing control unit bianco
After passing those rollers it also passes through another sensor which gives a clear idea how much bowing & skewing remain. The machine can run both manual & automatic mode. In case of dyed fabric generally it is run automatically because here bowing problem is minor & skew can control according to setup. But in case of printed fabric or yarn dyed fabric, the machine is run manually because here bowing & skewing control is more important. A simple negligence during operation can provide an unwanted design.
Chain gripping/ stretching unit: Here by means of mechanical application fabric shrinkage & width is controlled. Fabric comes from skewing bowing control unit is passed below two short expander rollers which ensure fabric open width entry. There is also few wheel brush for brushing the selvedge & to ensure proper gripping if the stenter gripping unit is pin type. If the unit is clip type then that is gripped automatically.There are ten gripper, , nine spindle roller, sixteen blowers. Here in chain two options can be provide:
Over feed
Ii. Under feed
Over feed: If the fabric width is higher than required & can not controlled in next stage then initially that is controlled slightly in this unit through over feed. Here the chain width is lower than the fabric width so that in heating zone fabric become relaxed. igher the over feed higher the shrinkage.
Under feed: If the fabric width is lower than that required then under feed is given. It is also called stretching. Through that fabric width cam be increased as required.
Under feed
Heating zone: After stretching unit fabric pass through heating unit. Here heat is provided according to finish. For Teflon finish temperature is around 180’c & for soft finish temperature is around 130-150’C. In this unit there are eight burners & sixteen blowers. Through hot air passing fabric is dryed. Here there is a screening unit to make safe heating & blower unit.
Cooling roller: After heating the fabric is passed over two stainless steel roller through which continuously cool water is passed. Due to this purpose fabrics become cool.
Fabric outlet: Finally the fabric is passed over through folding roller to fold on the storage bench. Then the fabric is ready for next process.
Fabric outlet
Monforst Stenter Machine
From control panel all types of instruction can be provide to the machinery. This machine has a full manual control panel. The operator controls every process by control switch.
