Choosing GSM for Corrugated Applications
Grammage (GSM) defines how much fibre you carry per square metre of paper. In corrugated packaging it drives stiffness, caliper, glue uptake, and cost—often more visibly than burst factor alone. Choosing the right GSM band is one of the highest-leverage decisions a converter or brand owner makes.
What GSM means on the corrugator
GSM (grams per square metre) is basis weight. Heavier GSM increases paper caliper and typically improves stiffness and crush-related performance, but also increases fibre cost and may require machine speed adjustments.
Medium and liner GSM are specified separately in a board combination (for example, 150 GSM medium with 180 GSM liner). Changing only one layer can shift ECT, BCT, and printability.
GSM bands we manufacture
At Nexa Papers, craft paper is produced from 90 GSM to 180 GSM, alongside BF 12–20, in natural and golden shades. That range covers many standard Indian corrugated programmes from light e-commerce boxes to heavier industrial shippers.
Matching GSM to application
Lightweight and retail-forward boxes
Lower GSM (roughly 90–120 GSM) on medium, with a stronger liner, can work for smaller cartons, die-cut displays, and programmes where print quality on the liner matters more than maximum stacking. Validate edge crush and drop tests before committing.
General industrial and agri cartons
Mid GSM (120–150 GSM) is widely used for medium in B-flute and C-flute boards serving produce, ceramics components, and engineering spares. Pair with liner GSM that matches stacking height and humidity exposure in the lane.
Export and high-stacking lanes
Higher GSM (150–180 GSM) on medium or liner supports demanding export programmes where container stacking and moisture variation stress the board. Overspecifying GSM without adjusting BF may add cost without proportional performance gain—test combinations holistically.
GSM vs caliper and runnability
Two mills may hit the same GSM with different caliper depending on refining and moisture. On the corrugator, caliper affects nip settings, warp, and glue consumption. When changing supplier, allow tuning time and monitor single-facer and double-backer behaviour.
Moisture at converting should typically be controlled in line with mill recommendations; see moisture and storage of kraft reels.
Cost and sustainability trade-offs
Reducing GSM by even a few points across a high-volume programme saves fibre—but only if box performance still passes your quality gate. Many brands now model GSM reduction alongside recycled fibre targets; discuss both with your mill so trials are planned, not reactive.
Checklist before you lock GSM
- Box dimensions, contents weight, and stacking layers (warehouse + transit)
- Flute profile and whether the grade is medium or liner
- Target BF band and shade (natural / golden)
- Print method on liner (flexo, offset lamination, etc.)
- Climate exposure (cold chain, monsoon humidity, export container)
Share this checklist with Nexa Papers marketing or operations when requesting a quote from Morbi.
Conclusion
GSM selection is structural and commercial. Start from box performance requirements, shortlist BF/GSM pairs, then trial on your line with realistic loads. Our team supports grade matching across 90–180 GSM for programme supply from Gujarat.