How to Buy a Used Case Erector and Case Sealer
A case erector and a case sealer do two different jobs at opposite ends of the same packing line. A case erector takes knocked-down carton blanks, opens them into a square box, and seals the bottom flaps so the case is ready to fill. A case sealer takes a filled carton and closes the top, and usually the bottom too, with tape or hot-melt glue. Sealers come in two families: a uniform sealer set up for one case size at a time, and a random sealer that adjusts itself on the fly to a mix of sizes.
Buyers shop these machines used because a well-kept erector or sealer is a long-lived, mechanically simple machine, and the price gap between new and used is wide. This guide is written for the people running end-of-line packaging: co-packers and contract packagers, e-commerce fulfillment operations, and food, beverage, and consumer-goods lines. It walks the same pre-purchase inspection an experienced packaging mechanic would run, so you can tell a genuinely good buy from a tired machine wearing fresh paint.
Tape Head vs Hot-Melt Glue
This is the first thing to identify, because it sets both run cost and what you inspect. Tape machines use a tape head cartridge and are cheap to maintain but cost more per case in consumable tape. Hot-melt glue gives a tamper-evident, lower-cost-per-case seal but adds a glue system, a melt tank, and nozzles that clog if maintenance lapsed. On a tape unit, check the tape heads for worn rollers, weak blades, and a dragging buff-down brush. On a glue unit, run it hot and watch for stringing, clogged nozzles, and a melt tank that does not hold temperature. A neglected glue system is the most common hidden cost on a used sealer.
Drive, Transport, and Side Belts
The side belts grip and move the case through the sealer, and they are a wear item. Look for glazed, cracked, or stretched belts, and uneven tension side to side that lets cases skew. Check the drive motor, gearbox, and any chains or timing belts for noise and play. Belts and a drive rebuild are not expensive on their own, but heavy belt wear is a good proxy for how many cases the machine has actually run.
Sensors, Photo-Eyes, and Controls Generation
Identify the control generation: relay logic, a basic PLC, or a current PLC with an HMI touchscreen. The generation drives spare-part availability and service support more than anything else on the machine. Confirm the photo-eyes and case sensors trigger reliably, and ask whether the PLC and drives are a current series or an obsolete one. An orphaned controller on an otherwise good frame is a real risk, because a control retrofit can cost more than the machine.
Frame Squareness and Alignment
A case erector or sealer only works if the frame holds the case square. Sight down the frame for tweaks from forklift hits, check that the compression sections are parallel, and look for cracked welds or elongated bolt holes at stress points. A bent or racked frame causes crooked seals and jams that no amount of belt adjustment fixes.
Case-Size Range and Changeover
This is the biggest fit question for a used buyer. Confirm the minimum and maximum case dimensions against the boxes you actually run, and find out whether changeover is manual hand-crank, has size memory, or is fully automatic. A semi-automatic uniform sealer that needs ten minutes of hand-cranking between sizes is fine for a single-product line and painful for a high-mix one. Match the changeover style to your case mix before you compare machines on price.
Vacuum and Blank Feed on the Erector
On a case erector, the blank pick is where most trouble lives. Check the vacuum pump and cups, the magazine that holds the knocked-down blanks, and the forming arms. Watch it pick and form real blanks, not a static demo. Misfeeds and double-picks at the magazine are the fault that slows an erector most, and they point to worn cups, a weak vacuum pump, or a magazine out of adjustment.
Guarding, Interlocks, and Safety
Confirm the guard doors, interlock switches, and emergency stops are present and functional, and that no one has bypassed an interlock to keep the line running. Missing guards and defeated interlocks are both a safety problem and a sign of how the machine was treated. Budget for bringing safety up to standard if anything is missing.
Maintenance Log and Realistic Throughput
Ask for the maintenance records and the machine's rated cases per minute, then ask what it realistically ran on the floor. Rated speed is a lab number; the sustained rate on your case size and seal type is what matters. A documented service history from a known plant is worth real money and tells you how the machine was maintained.
Which Machine Class Is Right for You
Use line speed, case mix, and labor to pick the class of machine before you shop on price.
| If you run | Look at | Why |
|---|---|---|
| Low to moderate volume, one or few case sizes, labor to load | Semi-automatic uniform sealer | Lowest cost; an operator sets the size and feeds cases. Good for single-product lines. |
| Higher volume, a mix of case sizes | Automatic random sealer | Adjusts to each case on the fly, so a varied size mix runs without manual changeover. |
| High volume, cases formed and filled in line | Automatic case erector plus sealer | The erector forms and bottom-seals so the line never waits on hand-made boxes; pairs with a sealer at the other end. |
Frequently Asked Questions
What is the difference between a case erector and a case sealer?
A case erector opens knocked-down carton blanks into square boxes and seals the bottom flaps, so the case is ready to fill. A case sealer closes a filled carton, the top and usually the bottom, with tape or hot-melt glue. They sit at opposite ends of the packing line, and many lines run both.
Tape or hot-melt glue, which is cheaper to run?
Hot-melt glue is generally cheaper per case and gives a tamper-evident seal, but it adds a glue system that needs maintenance. Tape costs more per case in consumable but the machine is simpler and cheaper to keep running. On a used machine, weigh the per-case consumable cost against the upkeep of the glue system.
What speed do I actually need?
Rated cases per minute is a lab figure. The number that matters is the sustained rate on your real case size and seal type, with your operators. Size the machine to your line's actual throughput with some headroom, not to the brochure peak.
Can one machine handle multiple case sizes?
Yes, but how easily depends on the machine. A semi-automatic uniform sealer changes size by hand and suits one or a few sizes. An automatic random sealer adjusts to each case on the fly and suits a high-mix line. Confirm the minimum and maximum case dimensions and the changeover style against the boxes you run.
What wears out first on a used case sealer?
The side belts that grip and move the case, and on glue machines the hot-melt nozzles and melt tank. On tape machines, the tape head rollers and blade. Heavy belt wear and a neglected glue system are the two most common hidden costs, so inspect both before you buy.
Keep Going
- Browse used packaging equipment on the marketplace.
- See live case erector and case sealer listings, or browse the full category if none are posted.
- Packaging equipment landing for the wider end-of-line picture.
- Pairing this with stretch wrapping? Read how to buy a used pallet wrapping machine.
- Manuals library for packaging machine documentation.
- Selling a case erector or sealer instead? List your equipment on the marketplace.