Product Specification

Upper-and-Lower Compound-Feed FIBC Sewing Machine for Coated PP Fabric Stitching

Sewing Challenges of Coated Woven Fabric

Coated PP woven fabric has a resin layer on its surface, so its friction characteristics may differ from those of uncoated woven fabric. If the upper and lower layers do not feed at the same rate, long seams may develop layer displacement, folded-edge deviation, or changes in seam position.

The DS9800 FIBC Sewing Machine uses an upper-and-lower compound-feed mechanism to support seam processing in coated PP woven fabric and multilayer bag-body materials.

How the Compound-Feed Mechanism Works

A conventional bottom-feed mechanism moves the fabric primarily from below. An upper-and-lower compound-feed system engages both sides of the material during sewing, making it suitable for multilayer bag fabric, folded edges, and combinations of coated and uncoated materials.

This mechanism provides direct feeding support for multiple layers, but it does not replace correct settings for presser-foot pressure, needle size, thread, and operating speed. Feeding performance should be verified with the buyer’s actual fabric.

Needle Holes Require Separate Evaluation

When the needle penetrates coated woven fabric, it creates holes through both the coating and the woven substrate. Needle-hole condition is affected by needle size, thread thickness, stitch length, sewing speed, and coating thickness.

A sewn seam should therefore not be described as waterproof or completely leakproof solely because coated fabric is used. If dust control or moisture protection is required, the buyer should also evaluate liners, sealing thread, or other seam-treatment methods through testing.

Three-Step Sample-Sewing Method

Step 1: Identify the Material Combination

Record whether the fabric is coated, the direction of the coated surface, the number of fabric and folded layers, and whether reinforcement fabric is included.

Step 2: Establish Initial Settings

Select a 7×230, 7×250, or 7×300 needle according to material thickness. Set the initial stitch length within the 0–14 mm range and begin at a speed that allows the stitch formation to be observed.

Step 3: Inspect the Sewn Sample

Check layer displacement, folded-edge deviation, skipped stitches, thread breakage, needle holes, and overall seam appearance. The approved sample can then be retained as a process reference for batch production.

Key Technical Specifications

Application

This FIBC Sewing Machine is primarily used for bag-body joining, side seams, folded edges, and reinforcement-fabric connections in coated PP woven bags, FIBCs, and jumbo bags. For fertilizer, cement, and mineral-powder packaging bags, the machine completes the seam-processing operation. Final moisture, dust, or leakage performance should be determined from the coating structure, liner configuration, and finished-bag test results.

FAQ

1. Does compound feed completely eliminate fabric displacement?

No absolute guarantee should be made. The mechanism helps move the upper and lower layers together, but feeding also depends on the number of layers, presser-foot pressure, operating speed, and machine settings.

2. Does coated PP woven fabric remain waterproof after sewing?

Sewing creates needle holes, so waterproof performance should not be claimed without seam testing. Liner and seam-sealing options should be evaluated when moisture or leakage control is required.

3. Which needle should be used for coated woven fabric?

The DS9800 supports 7×230, 7×250, and 7×300 needles. The final selection should be based on fabric thickness, overlapping layers, and thread size through sample sewing.