Paper Bag Making Machine

Plastic carry-bag bans have pushed shops toward paper bags, but the machines that make them are industrial-scale, expensive, and out of reach for a college lab — students usually study the process only from videos. The gap this project fills is a student-scale, fully visible paper bag making machine: kraft paper feeds from a roll, a triangular forming board folds it into a tube, an applicator roller lays the side-seam glue, a pressure roller seals it, and a serrated blade cuts the sealed tube into bag blanks. Every mechanism — feed rollers, chain reduction, forming geometry, glue application, cutting stroke — is exposed, labeled and adjustable, so the machine is a teaching rig as much as a working prototype. The bottom fold remains a manual finishing step, documented as a procedure the student performs on the cut blanks.

1. A kraft paper roll (design target 60–90 GSM, approximately 300 mm web width) is loaded on the spindle and the web is threaded through the steel nip rollers.
2. The operator switches on the 12 V drive and sets the feed speed with the PWM knob; the gear motor pulls the web forward through the chain reduction.
3. The triangular forming board folds the web edges inward into a tube while the adjustable side guides hold the selected bag width.
4. The glue applicator roller coats one folded edge with PVA adhesive from the pot, and the pressure roller seals the side seam flat.
5. The operator slides the serrated blade across the sealed tube at the stop position, cutting one bag blank per stroke; blanks drop into the collection tray.
6. The student takes the stacked blanks through the documented bottom-fold and bottom-glue procedure to finish each bag, verifying seam adhesion with the included peel test.

Tech stack:

• Aluminum extrusion + mild steel bolted frame
• 12 V DC gear motor (datasheet)
• Chain drive reduction
• Steel nip and pressure rollers
• Triangular sheet-metal forming board
• Glue pot + applicator roller (PVA cold glue)
• Serrated cross-cut blade on sliding bar
• PWM speed controller · fused 12 V supply

• [Motorized roll feed] A 12 V DC gear motor drives the steel feed rollers through a chain reduction, drawing kraft paper smoothly from the roll without hand feeding. A PWM speed knob sets the feed rate, so the demo can run slowly for explanation or faster for batch cutting.
• [Forming and folding station] A triangular sheet-metal forming board turns the flat paper web into a tube while adjustable side guides fold the edges inward. Bag width is set from approximately 15 to 25 cm by repositioning the guides — no rebuild needed.
• [Side-seam gluing unit] An applicator roller dips into a removable glue pot and lays a continuous adhesive line on the folded edge; a pressure roller seals the seam immediately after. The pot lifts out for cleaning and refilling between runs.
• [Cross-cut blade] A serrated blade on a sliding bar slices the sealed tube into bag blanks, with the cut position set by an adjustable stop for bag lengths from approximately 20 to 35 cm. The handle gives the operator positive, repeatable cutting strokes.
• [Collection tray] A bent-sheet-metal tray at the discharge end catches the cut blanks flat and stacked, its angled lip keeping the stack from sliding back under the blade. Blanks come off the machine ready for the bottom-fold procedure.
• [Bolted prototype frame] The frame is built from aluminum extrusion and mild-steel brackets joined with through-bolts — no welding — so every joint can be disassembled, measured and redrawn for the fabrication chapter of the report.
• [Labeled control wiring] A fused 12 V supply, stop switch and speed controller with reverse for clearing jams are wired in a labeled box; each station carries handwritten tape tags that match the assembly diagram in the documentation.
• [Bottom-fold procedure (manual, documented)] The prototype outputs cut tube blanks; converting them into usable bags needs a manual bottom fold and bottom glue line. This is documented as a step-by-step finishing procedure — an automatic bottom-fold station is future scope, stated openly.

• Working motorized paper bag making machine prototype
• Fabrication drawings (frame layout, forming board profile, roller arrangement, wiring)
• Bill of materials with sourced-part specifications
• Build and assembly documentation with station-by-station photos
• Bottom-fold finishing procedure sheet with seam peel test
• Project report PDF (background, mechanism design, fabrication, operation, testing plan)
• PPT presentation for final review
• Viva Q&A preparation document (paper feeding, forming theory, drives, gluing, cutting)