direct-sealed cans

Direct-Sealed Cans


The term "direct sealed can" describes a revolutionary development of the classic food can.In this case, an easy-peel membrane is sealed directly onto or into the can instead of the seaming of a separate metal end. This results in numerous advantages:

  • maximum convenience for the consumer
    • very low opening forces without tools (ideal for children and seniors)
    • no risk of injury as there are no sharp edges (as with the standard or easy-open end) as well
    • as good emptying properties as well as
    • recloseability on using a plastic lid.

  • cost minimization for the canmaker:
    • enormous savings in material costs due to the omission of a lid ring
    • simplified manufacturing process
    • lower investment costs compared to peel-off or easy-open-end manufacturing lines

Direct-sealed food cans made of tinplate essentially consist of three components:

  • the can body,
  • a direct-sealed membrane on the top end of the can, and
  • a metal bottom.
  • optionally, a plastic snap-on lid may be applied

The can body is produced on a can line, in which - compared to the classical food can - instead of a seaming module for metal bottoms, a direct-sealing machine for membranes is used.

The metal bottom is produced on a separate end manufacturing line. The bottom is seamed on direct-sealed cans only after the filling process.

A fully automatic manufacturing line for direct-sealed cans consists of several individual machines which are linked together by means of conveyor belts. At the customer's request, Blema supplies a complete turnkey system.

Through a unique Blema development three-part food cans in all formats can now be embossed, with the embossing exactly matching the decoration of the can.


Direct-Sealing to Curl [RHO III]

The membrane is sealed to an outer roll formed on the top of the can.

Application examples: cocoa powder, coffee powder, instant tea, peanuts, snacks, (sweetened) condensed milk

Direct-Sealing onto Flattened Ledge [RHO V]

A deep bead is formed from the can wall, which is then flattened and forms the sealing surface for the membrane. This results in a similar appearance as in the case of the peel-off ring. The advantage of the technology is that here the membrane can be sealed into the can at any depth, thus creating a headspace separate from the product as a place for additional tools (spoons) or gimmicks (brochure, toys).

Application examples: milk powder, baby food, oatmeal flakes, peanuts

The technology is currently suitable for dry bulk goods as well as hot-filled goods (e.g., condensed milk) without subsequent autoclaving. A solution for sterile-resistant filling goods is currently under development.

Manufacturing of Direct-Sealed Cans

Can bodies for three-piece tinplate cans are manufactured on a fully automatic production line comprising the following individual machines:


for the cutting of printed and / or lacquered blanks from sheets of tinplate

Transfer system

for the automatic feeding of blanks to the welding machine

Welding machine

for bending the blank into a tube and subseqent welding of the tube

Seam protection system

for applying a protective coating (powder coating or wet lacquer) to the inside and outside of the weld in order to avoid corrosion

Curing system

for heat-treating the protective weld coating

Combination machine

for final processing of the can body

The Blema-own, modular system GAMMA II allows for the individual combination of the following process steps in a machine for direct-sealed cans:

direct-sealing to top curl

  • necking the can ends (one or both sides)
  • flanging the lower can edge
  • roll forming on the top edge of the can
  • beading (to apply circumferential body beads, optionally)

direct-sealing to flattened ledge

  • roll forming on the top edge of the can (to protect the open cut edge)
  • flanging the lower can edge
  • deep beading - forming of a single deep bead (on the can circumference)
  • flattening the deep bead in order to create a sealing surface
  • beading (to apply circumferential body beads, optionally)


for inline differential pressure testing of unilaterally seamed cans


for automatic collecting of cans on pallets (multi-ply with inlays and stretch wrap)


die neckingdie flangingrail beadingdie flattening

hot contact sealing

roll neckingroll flangingroll beading
curl formingdeep beading

Machines for Direct-Sealed Cans

RHO III – Direct-Sealing Machine

RHO III – Direct-Sealer for Metal Cans (Top Curl)

RHO V– Direct-Sealer for Metal Cans (Ledge)

direct-sealing machines for metal cans in turret design

products: 3-piece tinplate cans with sealed-on membrane