Tin Box Structure

tin box tin can rectangle tin box cosmetic tin box

As the greater and greater varieties of products under the same product line are popping up at the markets, to have your brands stand out other ones on the same shelf, people are obliged to attach more and more importance to products package and package designs. They expect their package quality more superior,and their designs more characteristic and attractive.

Flexible bags and paper boxes are the most common packing choices. To pull the products out of others, some people turn to higher-end packaging material, yes, no doubt, it is metal tin packaging. This article would help the green hands in metal packaging know about tin box structures, and then a peaceful mind can accompany the whole tin box developing journey.

shore shelf products display on market

 How many pieces of tinplate piece is a tin box composed of?

Basing the tin’s construction, we can easily see tinplate pieces that forming up the tin: 2 pieces and 3 pieces are the most common.


2-pc seamless tin V.S. 3-pc seamed tin box

What is the 2-piece seamless tin?

That is tin lid and tin base – each is formed by one piece of tinplate, mostly they are formed by drawn or deep drawn, so they are also called as drawn tins.

As there are no seaming on tin bases, they are also called as seamless tins.

Or together they are called 2-piece seamless drawn tins.


What are advantages of 2-piece seamless drawn tins?

Seamless tin bases are composed of one piece of tinplate, so they are leaking proof. They are widely used in candle making industry and cosmetic industry.

The making way is punching and stretching, then it is easy to apply the automatic production lines, which save much labor and enhance the production efficiency; therefore, the seamless tins can be cost effective. These, to some extent, contribute to the wide usage and boom of some industries, such as scented candle making, solid perfume, and mint candies.

What are limitations for 2-pc seamless drawn tin cans?

All tins are made of tinplate, whose ductility is not as good as stainless steel or aluminum, even though its tenderness also lists from T1 to T4.

The tinplate material ductility poses the limitation: the drawn depth (tin body height) has to be less than tin diameter. If it is square or rectangle or special shape, the bigger the corner is, the closer to circle the corner is, the safer the tin developing and manufacturing is.

The tin tooling developing costs over USD1500, once there is no pioneer, better to stay conservative.


In addition, it is suggested to choose solid color or radial or expanding style designs. Wording and letters are better to stay away from the stretching skirt but to place at the flat area of bottom.

If the logo on the vertical base is a must, the tin factory would cooperate on the design modifications after stretching trials, round by round, it takes time.

The other option is to silk print or UV print the logo or wording on the vertical skirt. Silk print is for single color; UV is for multi colors, the former is much cheaper than the latter.


What is the 3-piece tin or Seamed tin?

3-piece tins are composed 3 pieces of tinplate, lid, body and bottom/end. They are also called seamed tins, as their bodies are seamed together from one side to the other firstly, and then formed into the final shapes. There are two seaming ways: welded seam and lock seam.

lock seamed tin can v.s. welded seamed tin can
lock seamed tin can v.s. welded seamed tin can

What is the Welded Seamed Tin?

Welding seaming is to have the two sides of body piece meet and attach together by the use of heating and melting.

What are Advantages of Welded Tins?

High speed automatic welding machine are widely used for welding, which is over 10 times faster than the traditional lock seaming way; thus, it saves time and cost. With glue applied around the top and end, the formed tins can be air tight and leakproof. Welded tin cans are commonly used in milk powder, paint, oil packing.

In addition, the welding connection is much sturdier than lock seam, and it could stand the partial horizontal swelling. If to have a vertical special shape rather than a round, square or rectangle, welding seam is a must.


What are limitations of welded tins?

To apply automatic welding line, it needs much larger MOQ.

As the coating and ink prevent the heating and welding process, the area along the welding line cannot be printed; that is the designs on the two sides cannot meet and combined together, but to leave a silver margin there. .


difference between lock seam and weld seam seaming machine v.s. welding machine
difference between lock seam and weld seam seaming machine v.s. welding machine

What is the Lock Seamed Tin?

Tinplate piece one side meets the other side and hooked together and then form into a shape. It is the traditional seaming way, since the making of the first tin can.

What are Advantages of Lock Seamed Tin Bodies?

It can be easily hooked and locked by labor with a locking machine; therefore, it is easy to widely apply, and the MOQ for this seaming way is much smaller than welded one. Also designs can apply on every corner and part of the bodies of this seaming way, and can meet and combine together at the seaming line.

What are Limitations of Lock Seamed Bodies?

Its air tightness is not as good as welding seaming, so it is widely used for packing hard stuff or bag packed products. And the bodies can only stay vertical, could not be swelled into special shapes.



What is Body forming or shaping?

With body two sides fixed together, the tinplate frame can be formed into any shapes: round easiest, square, rectangle, oval, octangle, hexagon, heart shapes, etc. With bottom/end piece assembled and fixed, and the shaped bodies are accomplished.


What is tin Bottom or tin End?

There are three bottom parts normally: lunch-box style, curl-out and curl-in.

Different tin box Bottoms

Lunch-box style: like what you see on lunch tin box, which has double lids, one of the lids is rivetted onto tin body, as worked as bottom.

Curl-out bottom is also known as seamed-on bottom. The bottom or end piece is seamed onto body by a seamer / seaming machine. The bottom piece rim shows when tin can is placed vertically.

Curl-in bottom is also known as clinched bottom, the bottom piece is clinched into body curl, bottom piece does not show when tins are vertically placed.


How Many Different Profiles of Tin Lids ? What are They?

It must be because lids are crowned head of tins, the tin box people present too many creations on lids, there are curl-out & curl-in, slide, slip, hinged & screwed, flat & step, plug-in, lever, clipped and so on. Let us see one by one.

tin box different lid styles different tin can cover profiles
tin box different lid styles different tin can cover profiles

Sliding lid is the lid that opens by sliding from one side to the other. Slide tin is always in rectangle shape, with 2-pc seamless structure; while also ok in 3-pc seamed structure when tin base needs to be too deep to drawn.

Curl-in or Curl-out lid:

Easy to understand that lid curl rolls inward or outward. Tinplate is to be rusted with time going, and the first place to get rusted is always the curl on the curl-out tin lid. If tins are preferred to always keep brand new, just have the lid curl inward.

Step lid: lid surface with step, so it can be stackable. Multi tins stack each other to save shelf space and to have better display effect.


Plug-in lid: that is the lid plugs into body, and the tin box in upright flush style. There are several common styles:

1-pc plug neck-in style, 1-pc plug in wine tin style, 1pc outer tin with the other piece attached as plug, the internal piece can be metal insert, tinplate frame, or plastic frame.

different styles for plug in lid profiles on flush style tin box tin canister
different styles for plug in lid profiles on flush style tin box tin canister

Slip or hinged: slip lid is removable, and hinged lid is hinged onto tin body.

Screwing lid: lids are with screwing threaded lines; screwing lines can be developed against the threads on tin body or glass jar. With rubber pad settled inside tin lid, it can be air tight.


Lever lid: like the top lid on the paint tin can, the lid can be quite tight; if to open, one hard and thin stuff is needed to lever it up. This kind lid is air tight.

Double-lids: there are two lids covered: one is inner, the other outer lid, the double lids ensure air tight enough.

air tight tin box with air tight tin lid cover double tin lid lever lid
air tight tin box with air tight tin lid cover double tin lid lever lid

Clipped lid: top lid can be made of tinplate, or injection plastic and clipped onto tin body. Top tin lid is always composed of two parts and with rubber pad added for air tight; plastic lid can be in custom color or in transparent clear.

different styles of clip lids on tin can tin box clip lids
different styles of clip lids on tin can tin box clip lids


What can we add up onto a tin box?

Besides these characters and advantages, we can also have the tins more functional by adding up accessories.

assessories on tin box clear window tin screw lid tin tin box with blister tray tin box with lock and pearl bead handle
assessories on tin box clear window tin screw lid tin tin box with blister tray tin box with lock and pearl bead handle

Clear Window: we can open window on tin lid or body or bottom, the window can be covered with hard acrylic or soft PET, safely fixed into tins; then interior products can be seen via the window.

The injection molded Plastic: plastic can be more solid and reliable when working as a connector between two tinplate parts, especially when working as connector as tall tin cannister or child resistant function locking system. Tinplate cannot be very accurate with the screwing threads and the tinplate hardness may be varied per different steel production runs.


Tray Inserts: the trays can be placed into tins for better setting of internal goods. Tray inserts can be made of paper, plastic, EVA foam, rubber, etc.


Lock System: multi locks can be rivetted onto tins, including the metal closure, coin bank lock with key, child resistant button lock and more.


Music module: ok to rivet music module onto tin, module rhymes can be customized, with switch for spring set on separate part of tin, the other part of tin can swirl around with music.

music tin box jack in the box tin box swirl music tin can carousel music tin can
music tin box jack in the box tin box swirl music tin can carousel music tin can


As we can see more and more different profiles of tin boxes are appearing in the market, either in different shape, or in novel structure. The consumers are getting more picky and always expecting to be irritated by unique and creative packages. Every industry is having innovation and progressing, so does the tin box industry. Let us keep an eye on what new ones are on the way.


At last, TinWonder Tin Box Factory is an over 10 years tin box manufacturer, focuses on tin box innovation and high-quality tin box production. Feel free to reach us, and Let us talk about tin box. Below video shows how tin boxes are made in our facility. 




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