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1. Thank you very much for buying a HIGH-SPEED OVERLOCK sewing

machine.

SUNSTAR will satisfy you by manufacturing the industrial sewing machine

with refined design, improved durability, great power, perfect performance,

variable functions based on skills and experience. 

2. Please read this manual thoroughly before use.

3. This manual can be changed the contents without prior notice to improve

the functions. 

4. This is designed and manufactured as an industrial machine. Do not use this

machine for other than its intended use.  

Summary of Contents for SC 7900-Series

Page 1: ...USER S MANUAL SC 7900 Series R 1 Readallinstructionsbeforeusingthe machinetopreventtrouble 2 Keeptheinstructionsandrefertoitduring machinefailures ...

Page 2: ...ine with refined design improved durability great power perfect performance variable functions based on skills and experience 2 Please read this manual thoroughly before use 3 This manual can be changed the contents without prior notice to improve the functions 4 This is designed and manufactured as an industrial machine Do not use this machine for other than its intended use ...

Page 3: ......

Page 4: ...6 7 AIR COMPRESSED TREAD TRIMMING DEVICE Optional INSTALLATION 17 8 AIR COMPRESSED DEVICE INSTALLATION 18 5 LUBRICATION 20 1 OIL 20 2 LUBRICATING OIL 20 3 OIL GAUGE OIL WINDOW 20 4 LUBRICATING OIL EXCHANGE 21 5 OIL PRIMING 21 6 LUBRICATING OIL REPLENISHMENT 21 7 OIL FILTER CLEANING 22 6 STANDARD ADJUSTMENTS 23 1 NEEDLE 23 2 NEEDLE INSTALLATION 23 3 THREADING 24 4 THREAD TENSION ADJUSTMENT 25 5 PRE...

Page 5: ...ER TIMING 35 7 STANDARD POSITION OF NEEDLE GUARD 36 8 FEED DOG HEIGHT SETTING 37 9 EXCHANGE OF PRESSER FOOT 38 10 EXCHANGE OF PRESSER FOOT SPRING PLATE A 40 11 BLADE EXCHANGE AND ADJUSTMENT 41 8 AIR COMPRESSED THREAD TRIMMER OPTIONAL MANUAL 43 1 CONSIDERATIONS BEFORE USING 43 2 MODEL NUMBER SETTING 43 3 SENSOR SETTING METHOD 43 4 RELATED PARAMETER 45 5 THREAD TRIMMING MODE SETTING 45 6 THREAD TRIM...

Page 6: ... package from the top in order Beware nails in wooden box Dust and humidity can cause pollution and corrosion of the machine Air conditioner should be equipped and cleaned regularly Do not expose the machine directly to the sun Allow at least 50cm of space on each side of the machine for convenient maintenance Explosion hazard Do not operate machine in explosive atmospheres where aerosol spray is ...

Page 7: ...witch is set to OFF before opening the cover of any electrical component or control box Turn the machine off when threading needles or inspecting the finished sewing Do not press the pedals when you turn on the power Install the machine away from strong electromagnetic wave such as high frequency welder as far as possible WARNING When you operate machine you should put the cover on to prevent phys...

Page 8: ...8 CAUTION STICKERS is attached on the machine for the safety Read thoroughly the manual before operating the machine ...

Page 9: ...9 ENTIRE STRUCTURES Arm Bed Head Arm support Arm support table Table Motor cover Spool thread stand Pedal Table legs ...

Page 10: ...ISO 406 605 608 General sewing knitwear 4 200 s p m in case of intermittent operations 1 6mm 2 5mm Stitches per 25 4mm 10 16 stitches per 30mm 12 19 Sewing machine needles Groz Beckert UY118GKS Retainer needles Groz Beckert UY36211 M5 5 2mm M6 6 0mm 30mm Type 01 8mm type 02 6mm at the highest point Adjustment link Max Forward differential feed ratio 1 0 1 5 Max Reverse differential feed ratio 1 0 ...

Page 11: ...11 INSTALLATIONS 1 TABLE INSTALLATION 1 Table type A Table B Arm support table ...

Page 12: ...12 2 Table installation Fix a dust bag with the screw like the figure 4 Assemble a control box like the figure 4 ...

Page 13: ...le and put a arm support table on it Set a buffer rubber onto the arm support connection then lift a arm support up Combine a clamp screw for the arm support putting cap nut and a nut with the arm support Combine the arm support table with the table using joint bots and nuts Combine the M C body with the arm support using the clamp screw ...

Page 14: ... the thread guide for stand support and then fix it with the screw Assemble the thread guide pipe 4 GROUND WIRE CONNECTION Connect a ground wire to the base cover and the control box Connect the ground wire to the base cover using a screw and a washer Penetrate the ground wire the hole A on the table Connect the ground wire to the control box ...

Page 15: ...sembled device with cylinder knuckles to the cylinder linking plate Assemble the cylinder linking plate with the arm support Adjust the cylinder knuckle to make the distance of 1mm between the cylinder knuckle short screw and the knee lifter connection lever Refer to the figure 9 1 Knee lifter connection leve Assemble the knee lifter connection lever with the screw ...

Page 16: ...r to the figure 12 Fix the coupling A to the main crank shaft Refer to the figure 13 Assemble the motor parts and the motor cover Refer to the figure 11 6 DIRECT MOTOR INSTALLATION Assemble the arm fix bracket and the assembled part with the arm Refer to the figure 11 ...

Page 17: ...essed thread trimming device is composed of several parts G CT 0002 Assemble the thread cutting block and the thread cutting base at the center of the front and the side Refer to the figure 15 You should be careful no to intrude into the sensor part when setting the suction pipe ...

Page 18: ...he lower fitting of the air compressed cylinder and the right side of the upper solenoid valve Connect the air hose to the suction pipe and the lower solenoid valve Connect the cable which is written in PF linking to the control box to the upper solenoid valve Connect the cable which is written in CL linking to the control box to the lower solenoid valve After installing to the table open the air ...

Page 19: ...noid valve A Connect the air hose to the suction pipe and the solenoid valve B Connect the air hose to the cutter cylinder and the solenoid valve C Connect the cable which is written in PF linking to the control box to the solenoid valve A Connect the cable which is written in CL linking to the control box to the solenoid valve B Connect the cable which is written in TT linking to the control box ...

Page 20: ...e machine without breakdown remove the oil cap screw and then lubricate oil to the top limit of the oil gauge 3 OIL GAUGE OIL WINDOW Check the oil gauge before operating the sewing machine Lubricate oil when the oil indicator or the oil surface refer to the figure 18 19 is under the 2 lines Check the spattering of the oil through the oil window when operating the sewing machine ...

Page 21: ...y Refer to the 2 LUBICATING OIL for lubricating 5 OIL PRIMING Prime the oil before operating new machine or the machine not to use for a long time After remove the upper screw of oil pump housing and oil priming then fix it again with the screw Refer to the figure 22 6 LUBRICATING OIL REPLENISHMENT Lubricate about 3 4 drops of oil into the oil hole Figure 23 every one time a month If the oil leaks...

Page 22: ...fix the oil outlet screw firmly Separate the oil pan from the bed by loosening the oil pan clamp screw Remove the foreign substances by pulling out a oil filter Assemble it again in reverse order Refuel referring to the 2 LUBICATING OIL Suction filter cleaning Separate the oil pump by loosening the oil pump fixation screw Remove the foreign substances of the suction filter Assemble it again in rev...

Page 23: ...the various size of needle 2 Retainer needle This sewing machine uses the UY36211 sized needles made by from Groz Beckert Select the proper needle according to the thickness and type of the sewing materials because of the various size of needle 2 NEEDLE INSTALLATION Loosen the clamp screw Remove the old needle using the tweezers Lift the needle to the end of needle hole and then fix it firmly by t...

Page 24: ...roblems can be happened such as stitch skip thread cutting irregular tension etc A B C and D are the needle thread E is the fancy thread F is the looper thread After threading cut the scrap of thread before stitching Do the same for the looper thread and the fancy thread ...

Page 25: ... looper thread 1 Presser foot lifting adjustment Set the distance between the presser bar lifting lever and the presser bar linking bracket to 1mm when the presser foot is near the needle plate Refer to the 6 7 VERTICAL ADJUSTMENT OF PRESSER FOOT This is the standard Adjustment order a Remove the rubber cap b Undo the screw in the presser bar lifting lever link large size c Adjust the distance by ...

Page 26: ...ted a little and the upper and lower plate of the thread adjusting device plate are attached together Adjustment order a Loosen the clamp screw in the presser bar lifting lever large size b Adjust the thread release shaft by rotating with a driver 6 PRESSER FOOT PRESSURE ADJUSTMENT To make the presser foot pressure lower is better as far as the sewing material is moved well and the stitch is forme...

Page 27: ...plate prevent the feed dog damage Fix it by tightening the pressure adjustment fixation nut firmly 8 MAIN FEED ADJUSTMENT The stitch length can be regulated from 1 6mm to 2 5mm basically and it is able to be regulated more or less than the value The following table indicates the stitches per 25 4mm and the stitches per 30mm Loosen the needle guard back clamp screw and move the needle guard to the ...

Page 28: ...le guard back clamp screw firmly 9 DIFFERENTIAL FEED ADJUSTMENT To adjust the differential feed dog rotate the differential feed operating lever to the left or the right If the differential feed operating lever is on the 4 or 5 the momentums of the main feed dog and the differential feed dog will be the same For the forward differential turn the differential feed operating lever to the scale of 9 ...

Page 29: ...he amount of oil on occasion opening the silicone oil cap 11 OVERLAP WIDTH ADJUSTMENT OF UPPER SEWING MACHINE 1 Standard position of the lower knife Set the distance between the lower knife and the lower knife holder to 0 0 5mm Refer to the Figure 41 2 Standard position of the upper blade Set the distance between the upper knife and the lower knife to 0 5mm when the upper knife is on the most left...

Page 30: ...p screw and adjust the position of the lap former according to the edge of the overlapping sewing materials or the feed direction of the fabric 2 Front Rear standard position Set the lap former at the position which the lap former slide block and the needle plate are attached Adjust the lap former front and rear depends on the thickness of the cloth ...

Page 31: ...fix it by tightening thread pin clamp screw Loosen the thread pin clamp screw Set the height of the thread pin and the thread pin 1 6mm above Then fix it by tightening thread pin clamp screw Loosen the thread pin clamp screw Set the height of the thread pin and the thread pin 3 2mm above Then fix it by tightening thread pin clamp screw 2 Thread guide adjustment Make the thread guide hole height of...

Page 32: ...g adjustment The timing setting standard of the looper thread take up is to set the looper thread through the point A when the needle bar goes down 2 8mm from the highest point Loosen the looper thread take up clamp screw and adjust like above then fix it by tightening the clamp screw Refer to the Figure 47 3 Looper threads take up lever eyelet standard position Set the looper thread take up lever...

Page 33: ... and set it in order 2 Upper thread take up lever timing adjustment When the upper thread is seized by the upper thread holder set the upper thread to 0 1mm position from the highest point of the thread take up lever which is point A in the Figure 46 Loosen the upper thread take up lever clamp screw and tighten the clamp screw When the needle bar is at the highest point the height of the 4th end o...

Page 34: ...r thread retainer clamp screw Then set according to the fixation by tightening the upper thread retainer clamp screw 2 Upper thread holder standard position When the upper thread holder is at the closest to the upper thread retainer set the distance between them to 0 4 0 7mm When the upper thread holder is at the end of the right direction set the distance between the upper thread holder and the r...

Page 35: ...g the clamp screw firmly Refer to the Figure 54 3 Front back position of the looper and the needle When the looper moves from the left to the right the looper should pass through behind the needle Refer to the Figure 55 Set the distance the looper and the needle to 0 0 05mm to make the looper is at the closest to the needle Set the looper not to attach to the needle Refer to the Figure 55 When rot...

Page 36: ...end of the looper meets the center of the first needle on the left Then fix it by tightening the needle guard front fixation screw 2 Standard position of the needle guard rear Open the looper cover and loosen the needle guard rear fixation screw When the needle guard rear is at the closest to the needle adjust the distance to 0 05 0 1mm and then fix it by tightening the needle guard rear fixation ...

Page 37: ...ain feed dog clamp screw Fix the differential feed dog by tightening the differential feed dog clamp screw after loosening the differential feed dog clamp screw and adjusting the height of the main feed dog and feed dog horizontally Refer to the Figure 60 61 2 Fine tuning of the feed dog After fine tuning the feed dog height with the feed bar eccentric pin by loosening the feed bar eccentric pin c...

Page 38: ...ure 63 Loosen the presser bar adjusting screw and the presser bar connection bracket clamp screw Refer to the Figure 63 Loosen the knife holder guide clamp screw Refer to the Figure 64 Loosen the knife holder shaft support bar clamp screw and remove the knife holder shaft support bar A Refer to the Figure 65 ...

Page 39: ...spring Refer to the Figure 67 Remove the thread holder crank from the hook drive sleeve Refer to the Figure 68 Remove the presser foot among the presser foot guide left right by turning the presser foot to the left Refer to the Figure 68 Insert the replacement presser foot in the presser foot guide left right by turning to the right Refer to the Figure 68 Insert the thread holder crank into the ho...

Page 40: ...e bar is at the lowest point and the presser foot is closest to the needle plate insert the presser bar pressure adjusting spring and adjust the presser bar pressure with the presser bar adjusting screw by referring to the 6 6 PRESSER FOOT PRESSURE ADJUSTMENT Then tighten the presser bar connection bracket clamp screw by pressing the presser bar connection bracket slightly and fix it Close the rub...

Page 41: ...mp screw after adjusting the knife holder guide by loosening the knife holder guide clamp screw 2 Knife removal Remove the knife upper by loosening the knife holder guide clamp screw and the knife clamp screw Remove the lower blade by loosening the lower blade holder clamp screw 3 Knife reinstallation Fix the replacement lower blade with the lower blade holder clamp screw and fix the knife upper w...

Page 42: ...42 4 Adjustment of the knife upper and lower blade meshing angle Disassemble parts in order then adjust them by turning the setting screw B Refer to the Figure 74 ...

Page 43: ...ing 8 3 SENSOR SETTING METHOD Put the end part of the sewing material at the front before sewing 2 MODEL NUMBER SETTING 3 SENSOR SETTING METHOD 1 Sensor setting Sensor position Make a sensor lamp and a needle bar in a straight line Check the normal operation of a sensor Turn the power on without sewing materials When the sensor lamp comes on it means that the sensor operates normally needle bar se...

Page 44: ...not sewing material and goes out when there is sewing material like Check the normal operation of a sensor 2 Clearance between the sensor and the thread trimming device The clearance between the sensor and the thread trimming device is about 36mm and the cutting stitch number should be decided by considering this clearance and the stitch length The basic setting value is the 2mm pitch Related para...

Page 45: ...METER 5 THREAD TRIMMING MODE SETTING 1 Manual thread trimming mode by the knee switch Pedals in the neutral position before sewing Pedals in the neutral position during sewing Pedals in the neutral position after sewing ...

Page 46: ...er detecting the sensor When the movement stops the initial cutting and the final cutting start operating thread trimming process 4 Operation process of Auto thread trimming mode 3 feature During pressing the pedals the value is sent to the setting value by counting the stitches after detecting the sensor Then the initial cutting starts working when taking your foot off the pedal After that the se...

Page 47: ...47 6 THREAD TRIMMING RANGE SETTING ...

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