Frequently Asked Questions
Everything buyers ask us before their first order — samples, minimums, lead times, printing, payment and quality control.
Ordering, samples and minimums
How do I place an order?
Email us your specification or fill in the inquiry form. We will confirm the specification, send a price and a quotation, and produce a pre-production sample for your approval before mass production starts. Once the sample and the artwork are approved, we invoice the 30% deposit and start production.
Can I get free samples?
Yes. Standard stock bags are free — you cover the courier cost only. Customised samples printed to your own specification and artwork carry a small sampling charge because they need a plate and a line change. Samples are normally ready within 7 days and ship by DHL, FedEx or UPS.
How long does a customised sample take?
Usually 7 to 10 days from artwork approval. If your requirement is urgent, tell us and we will check what can be moved in the production schedule.
What payment terms do you offer?
Our standard terms are 30% T/T deposit with the balance against the copy of the bill of lading, or the full amount in advance. We also work with L/C at sight on larger orders. Payment terms for a first order are always confirmed in writing on the quotation.
Production and delivery
What is the production lead time?
Around two weeks for bags with no customisation. Fully customised bags take up to 25 working days from artwork approval. We give you a firm production date on the order confirmation and we update you if anything changes.
How do you ship?
Sea freight FOB or CIF is the normal choice for container volume, and air or courier for samples and small trial orders. We work with your nominated forwarder or we can arrange shipping and give you the full document set for customs clearance.
Can you send loading photographs?
Yes, as standard. Before the container leaves we photograph the loading, the bale or pallet count and the carton markings, and send them to you with the packing list. If you want a third party inspection instead, SGS, BV or Intertek are all welcome at the factory.
Specification and printing
Can you copy an existing bag I send you?
Yes, and it is the fastest way to an accurate quotation. Post us one bag, or send photographs with the dimensions, and we will reverse engineer the fabric weight, construction and print specification, then quote against it.
What artwork files do you need?
Vector artwork in AI, EPS, PDF or CDR is ideal. High resolution PNG or JPG also works if the resolution is good enough. If all you have is a logo (or a photo of a competitor bag), our designers will lay out the artwork for you and send a proof for approval.
Do you charge for print plates or cylinders?
Print cylinders are a one-off cost per colour per design and they are yours. We store them, so reorders carry no plate cost. We will quote the cylinder cost alongside the bag price so there are no surprises.
Quality and certification
What quality control do you apply?
We operate an ISO 9001:2015 quality management system, with inspection at fabric, print, converting and final packing stages, and batch records kept against your order so any problem can be traced back to the loom and the shift that produced it.
Can I visit the factory or inspect remotely?
Yes. You are welcome to visit us in Wenzhou, and if travel is not practical we will schedule a live video inspection of your production run on a call at a time that suits your timezone.
Are your bags food grade and UN certified?
Our factory is approved to produce standard food grade bags and UN certified bags for dangerous goods, with strict quality control. Certification is specific to the material and the construction, so tell us which market and which regulation applies and we will confirm what we can provide.
Technical questions about the bags
Can I get free samples of your PP woven bags or kraft paper bags?
Yes. Standard stock bags are free of charge — you only cover the courier cost. If you need a bag made to your own specification and artwork, we produce a customised sample for a small sampling charge. Most samples are ready within 7 days and can be sent by DHL, FedEx or UPS.
What is your minimum order quantity?
We support low minimum order quantities for a first order so you can test the quality and the market before scaling up. Standard production runs start from one 20ft container, and we will tell you honestly what MOQ applies to your exact size, material and print requirement.
How long is production and delivery?
For bags without customisation, production is usually around two weeks. Fully customised PP woven or multi-layer paper bags take up to 25 working days after artwork approval. Shipping time depends on the destination port — we will quote you ocean transit days with the offer.
What is the difference between a laminated and an unlaminated PP woven bag?
An unlaminated bag is plain woven fabric: strong, breathable and the cheapest option, best for grains, feed and products that must not trap moisture. Lamination adds a film layer — PP laminated or BOPP laminated — which closes the weave, stops fine powder escaping and gives a smooth surface for high quality printing. If your product is a fine powder or you sell from a retail shelf, laminate it. If it needs to breathe, do not.
How do I choose the fabric weight (gsm) for my bag?
Work backwards from the load and the stacking. A 25kg bag of grain usually runs comfortably at 70 to 80 gsm; a 50kg bag of dense fertiliser or a bag that will be stacked five high needs more, often 90 to 110 gsm, and may need anti-slip weave. Tell us the product, the bag weight and how high the pallets are stacked and we will specify the fabric weight, and explain the reason.
What does multi-layer mean, and how many plies do I need?
Each ply is a separate paper layer glued together, and the plies share the load. A light retail sack might be two plies; a 25kg cement or fertiliser bag is typically three or four plies, and a heavy-duty chemical bag can be five. The right number depends on the weight per bag, the drop height in your warehouse and how the bag will be stacked. We usually start from the product and the filling line, then specify plies, paper grammage and any intermediate liner.
What is the difference between PVSE, PBOM, SOM and block bottom?
PVSE is a pasted valve bag with a sewn easy-open end — filled through the valve and opened along the sewn edge. PBOM is a pasted bottom open mouth bag, filled from the top. SOM is sewn open mouth, closed with thread after filling. Block bottom (also called SOS, self opening sack) is a folded block base that lets the bag stand up on a shelf. Valve closures suit fast automatic filling of powders; open mouth constructions suit granules, seed and products filled by weight.
Ask us anything about your packaging
No obligation, no hard sell. Describe what you pack and we will tell you what bag you need, what it will cost and how long it takes.
- Emailsales@unisunpack.com
- Tel / WhatsApp+86 15825665852
- FactoryWenzhou, Zhejiang Province, China 325000
- Response timeWithin 24 hours, Monday to Saturday