Hardware is the category where packaging machines go to find out how strong they really are. A bag of screws is heavier than it looks, every piece has a sharp point, and the product does not care that your film was specified for biscuits.
The good news is that hardware packaging is also one of the most profitable things you can automate, because the labour cost of counting small parts by hand is brutal.
Three ways small parts break film
Puncture. A screw tip or a drill bit corner arrives at the seal with a point. Once the film is pierced, the bag fails slowly and arrives at the customer empty or half empty.
Abrasion. Fasteners rub against the inside of the bag in transit, thinning the film until it fails at a fold. Threads are particularly good at this.
Corner impact. A bracket or hinge drops into the bag and hits the bottom seal at speed. On a vertical machine this is the most common failure, and it gets worse as you increase speed.
Film choice, and why thickness is not the whole answer
More microns helps, but structure matters more. A 90 micron coextruded PE will puncture more easily than a 70 micron laminate with a PET or nylon layer, because the oriented layer spreads the impact instead of splitting.
For sharp, heavy parts, ask for a structure with an abrasion-resistant outer layer and a puncture-resistant core, and test it by dropping a filled bag onto a concrete floor from a metre. That test tells you more than any datasheet. Paper-faced laminates are popular for the retail hardware look and hold up reasonably well, as long as the inner layer is strong.
Count or weigh
For identical parts, weighing is faster and cheaper. A counting scale with a piece-weight memory will get you within a piece or two on a 100-piece batch, and a multihead or linear weigher will run at production speed.
For mixed kits, you need something else: a multi-lane counting system, a small bowl feeder per component, or manual assembly into a tote that feeds the bagger. There is no elegant machine that counts six different part types into one bag at high speed for a reasonable budget, and anyone who says otherwise is selling you an integration project.
Kits are a packaging problem, not a counting problem
Most DIY kits fail commercially because of the packaging, not the parts. A bag with six loose components arrives as a bag of scratches. Options that work:
- Small components in a printed poly bag, dropped into the outer bag with the large parts
- A compartmented tray or a skin pack card for retail hanging
- A bag-in-box with a printed insert card
- Shrink-wrapped bundle for matched sets
Each of those is a different machine or a manual station. Plan the kit architecture before you buy the bagger, because retrofitting a card inserter into a finished line is expensive.
Which machine for which product
| Product | Machine | Why |
|---|---|---|
| Screws, nuts, washers in 50 to 500 g bags | VFFS with counting or linear weigher | Fast, cheap bag, good for bulk retail |
| Drill bits, blades, hand tools | Flow wrapper with product infeed | Product is placed, not dropped, so no puncture at the seal |
| Brackets, hinges, heavy fittings | Heavy-duty flow wrapper | Reinforced jaws and a film path built for weight |
| Mixed kits with a card | Premade pouch machine with inserter, or manual | Bag opens wide, card and parts load together |
| Retail hanging packs | Flow wrapper with hang-hole punch | Punch and seal in one pass |
For heavy hardware, a flow wrapper with a reinforced frame and a product conveyor is usually the better answer than a VFFS, because the product is supported on the film rather than dropped onto a seal. Our Flow-600 hardware flow wrapper is built for exactly this, and the flow wrapper range shows the sizes around it.
Static, oil and rust
Three small details that cause large arguments with customers:
- Static. Dry, cold workshops make film cling and small parts jump. An anti-static bar at the infeed costs little and fixes a lot
- Oil. Machined parts arrive with cutting oil on them, which migrates to the seal and weakens it. Ask for a degrease step, or specify a film that seals through light oil
- Rust. A sealed bag with residual moisture rusts parts in transit. A desiccant sachet, or a VCI film for long sea freight, is cheaper than a rejected container
Speeds and expectations
A flow wrapper on hardware typically runs 40 to 80 packs a minute depending on product length and how much the operator has to place by hand. A VFFS on 200 g bags of fasteners runs 40 to 60. Counting accuracy, not machine speed, is usually the real constraint, so measure your counting station before you buy a faster bagger.
One last practical note: hardware buyers open bags with knives and expect the bag to survive a warehouse. A 20 percent thicker film costs a fraction of a cent per bag and prevents most of the complaints you would otherwise spend the year answering.
Frequently asked questions
What film is best for screws and sharp parts?
A laminate with a PET or nylon layer, 70 to 100 micron total, rather than a thick coextruded PE. The oriented layer resists puncture far better at the same thickness.
Can I weigh instead of count?
For identical parts, yes, with a counting scale that stores piece weight. For mixed kits, no, because weight cannot tell you whether the mix is correct.
Why do bags fail at the bottom seal?
Product impact. The parts fall onto the seal before it has cooled. Slow the drop, add a product cushion, or switch to a horizontal machine that supports the product on film.
Do I need a hang hole?
Only for retail pegboard display. It is a punch tool on the machine, and it needs to be specified at order time, not added later.