This document is an instruction manual for the TN-700D Series Sewing Machine, specifically covering the TN-737D, TN-747D, and TN-757D models. It provides comprehensive guidance on operating, maintaining, and adjusting these industrial overlock sewing machines.
Function Description:
The TN-700D Series Sewing Machines are industrial overlock machines designed for various sewing operations, primarily overcasting seams. The series includes models for different thread configurations and material types:
- TN-737D: A 3-thread, single-needle overlock machine, traditionally used for overcasting edge seams on both knit and woven materials.
- TN-747D: A 4-thread, two-needle overlock machine, commonly used for knits and ready-to-wear garments. This model forms an overedge stitch with two needle threads and two looper threads.
- TN-757D: A 5-thread, two-needle overlock machine, primarily used for woven materials. It can perform both 3-thread overcasting and 5-thread overcasting with a safety stitch. This model is not recommended for knits.
Important Technical Specifications:
The technical specifications vary slightly by model, primarily in the seam type and thread configuration, but share common characteristics:
- Seam Specification:
- TN-737D: ISO# 504 Overedge (1 needle thread, 2 looper threads).
- TN-747D: ISO# 514 Overedge (2 needle threads, 2 looper threads).
- TN-757D: ISO# 516 Safety Stitch (single-needle chainstitch 401 and 3-thread overedge stitch 504 simultaneously).
- Sewing Capacity: Up to 5mm for all models.
- Standard Needle: B27 (DCx27) #10/70~14/90 for all models.
- Stitch Length: Up to 6 mm for all models.
- Speed: Up to 5000 stitches per minute, depending on thread, fabric, and sewing operation for all models.
- Machine Weight: 48kg.
Usage Features:
- Installation: The manual provides detailed instructions for machine installation, emphasizing that it should be carried out by a qualified technician due to the machine's weight (48kg) and electrical connections. It specifies the placement of the motor pedal (left side) and presser foot lift pedal (right side), as well as the installation of the waste chute and thread stand. It also details semi-submerged (100mm from needle plate to table surface) and fully-submerged (5mm) table installations.
- Handling: Clear instructions are given on how to safely lift the machine, emphasizing the use of proper lifting techniques and warning against lifting by the left base arm.
- Break-in Period: A break-in period is recommended, operating the machine at 80% of maximum speed for the first two weeks to extend its life and allow new parts to "break-in."
- Threading: The manual includes detailed threading diagrams for each model (3-thread, 4-thread, and 5-thread configurations) to ensure correct thread path, which is crucial to prevent thread breaking, stitch skipping, puckering, or unexpected sewing issues.
- Tensions: Thread tension adjustment is critical and depends on the material type, thickness, stitch length, and seam width. The manual explains how to adjust the individual nuts for each thread (double chain stitch, left overlock needle, seam lock needle, upper looper, lower looper, and double chain looper threads) to increase or decrease tension by turning them clockwise or counter-clockwise, respectively.
- Needles: Users are instructed to use DCX27 needles or equivalents. The process for loosening, removing, inserting, and tightening needles is described, with an emphasis on seating the new needle firmly and correctly (scarf facing the back, long groove facing the operator). A crucial safety caution is to turn off the main power switch before changing needles.
- Stitch Length Adjustment: The stitch length can be adjusted by pressing a button (1) and turning the pulley until the button locks, then releasing it at the desired stitch length. This adjustment is dependent on fabrics, differential ratio, and other factors.
- Differential Feed Adjustment: This feature allows control over fabric stretching or shrinking during sewing. Loosening an adjusting nut (1) and moving an adjusting rod (2) downward shrinks the fabric, while moving it upward extends it. A table provides differential feed ratios for different scale settings.
- Blade Adjustment/Replacement:
- Upper Blade Replacement: Involves loosening screws, moving the lower blade holder, removing the old blade, inserting a new one, and adjusting its height so it crosses the lower blade by 0.5-1.0 mm at its lowest dead point.
- Lower Blade Replacement: Involves loosening screws, moving the lower trimmer holder, replacing the blade, and adjusting its top edge to align with the needle plate surface.
- Hem/Cutting Width Adjustment: This adjustment is made by moving the upper blade holder left or right after loosening a screw (3) to achieve the desired cutting width.
Maintenance Features:
- Lubrication: The manual details how to fill the lubrication oil by removing a screw (1) and filling with high-speed oil until the level indicator is between the MAX and MIN lines. It also explains how to drain oil by loosening a screw (2), reminding users not to lose the drain plug washer.
- Filter Change: For yearly maintenance, the oil filter, located on the backside of the machine, can be changed by removing three screws holding its cover.
- General Safety: Emphasizes keeping the work area clean, operating in a safe environment (avoiding wet areas), keeping children and pets away, dressing properly (no loose clothing/jewelry), inspecting cables, maintaining the machine with care, disconnecting power when not in use or during adjustments, and only using authorized parts or qualified repair personnel.
- Safety Labels: Explains various safety labels, including "DANGEROUS" (risk of serious personal injury), "CAUTION" (risk of machine/operator damage), "Moving parts," "High voltage," "High temperature," "Prohibited," and "Grounding wire." It stresses the importance of reading the motor supplier's safety rules as well.
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