What Does Sift Proofing for Bulk Bags Mean?

While you may have heard the term 'sift proofing' regarding bulk bags, you may not know what that means.

For this latest blog, Centurion Packaging will guide you through everything you need to know about sift-resistant proofing and how it relates to your woven polypropylene sacks.

Sift Proofing Explained

Sift proofing is the steps a bulk container manufacturer takes to prevent leakage of product from the bag through the seams. Leakage will lead to a lost product, which ultimately will cost your company money and could mean excess product ends up on the factory floor could cause increased health and safety hazards. The established method of sift proofing is sift-resistant sewing, which is also referred to as anti-sift sewing.

Anti-sift sewing is the most common method that manufacturers currently use for sift proofing of bulk bags. This procedure involves sewing a soft yarn or a special felt into the seams of the bag. While sewing, the operator keeps the sift cord along the bag's seam so it fills the spaces by the needle hole.

What is a Sift-Proof Seam?

A sift-proof seam is felt or downy material attached to the seam as part of the sift proofing process. Leaks do happen because the sewing needle can make minuscule holes in the fabric, which won't be a problem for most dry goods but for fine powder goods like milk or cocoa powder, the displacement caused by air in the bag can lead to some of the material to escape through the holes in the seam.

Attaching the sift-proofing material prevents any goods from escaping through sifting or leaking. The sewing operator will be able to sew the felt next to the threaded sift cord or in between fabric panels.

Are There Other Ways to Prevent Sifting?

When constructing sift-proof woven polypropylene sacks, the yarn or felt needs to be thick enough to cover the needle holes. Using too thin of material can mean the product will escape during or after filler. Additionally, the use of polyethylene liners can act as a sift-proof method that ensures no leakage happens.

Get in Touch With Any Bulk Bags Questions

If you have any questions about sift proofing for bulk containers, please do not hesitate to contact Centurion Packaging today.