Products and equipment for rubber stamp making

Rubber stamps are mainly used for administrative applications, as a   signature of a company, administration, commercial entity or individual. However other kind of stamps are available, such as daters specifically used to date documents or numberers to affix numbers on document series.

In France, company stamp  is required to process most documents such as contracts, quotes or delivery notes.  Signature is generally made next to or on the company stamp, with date.

Stamp is also widely used in scrapbooking applications, to customize creations : cards, announcements, albums, Christmas cards, birthdays… Multiple accessories are available for using rubber stamps in a different way : embossing powder, multi-color ink, metallic inks ...

Finally, stamps are also used in specific applications: outdoor use with UV inks, tracking information (for instance  ampoules,  with acid inks), textile marking for  clothes…

Historically, texts were arranged and images were engraved by typographic workers then gathered together  and tightened inside a forme. Then a matrix made of wax and other materials was placed on top and the whole  was placed inside a heating press to imprim patterns inside softened wax.

After cooling, the wax mold was covered with rubber and parchment paper  and placed again in the heating press so  that rubber can flow inside mold depth and produce relief for stamps. The resulting rubber sheet was cut into stamps.

Development of computers allowed to give up cumbersome manufacturing tools (lead character fonts, presses..) and use computer-aided publication and photosensitive polymers

Now, stamp manufacturing process consists of several easy steps:
-  patterns to be reproduced are drawn on a computer
-  a film is printed to get a negative
-  photopolymer  liquid resin is exposed through the negative to get a photopolymer stamp, or hard photopolymer plate is exposed to produce a cliche

- photopolymer cliche is pressed into a matrix board to get a mold for rubber (rubber stamps) or premix gel (pre inked stamps) moulding
 

« stamp »  word can include inking pad,  box containing ink pad, instrument used to transfer a print on a document and even final print. Stamp can be manual or automatic.

Our company offers products for  the  “seal”  technical part of the stamp  : part in rubber, photopolymer or pre inked material with characters,  logo or drawing to print.

In case of rubber or photopolymer resin, stamp surface should be coated  with ink from an ink pad. Then, stamp is placed above support and pressure is applied to transfer ink from stamp surface to the support. For another print, it is necessary to ink again stamp surface.

In case of pre-inked material,  ink is directly contained in the microporous structure of the stamp (ink capsules).

Production of conventional or laser rubber stamps requires no special layout. Working space should be large enough for accomodation of necessary equipment and include some space for assembling stamps to mounts and for storing devices.

Some odor may be released during production, room must be well ventilated or, for more comfort, equipped with a controlled mechanical ventilation.

To produce stamps for scrapbooking , the same pattern should be molded several times to get several copies of the same stamp : each model is ordered several times by several customers.

In conventional rubber stamp manufacture, a photopolymer plate (with patterns in relief) is pressed into a matrix board, in a heating press,to produce a mold (with patterns in depth). Rubber is pressed in the resulting mold to produce final stamp.

Once the mold with patterns in depth is obtained, it can be stored and re-used  according to request : it is possible to mold again a single stamp or a complete plate with only rubber as raw material.

So conventional rubber stamp is the fastest and cheapest technique,

Other techniques requiring to redo all processing steps, they are not so interesting for scrapbooking.

Two techniques  are possible, with two different equipment

Laser engraved rubber stamps

It is necessary to have a laser engraver : see our Eko or industry laser ranges.

The higher the power chosen,the faster stamps will be engraved.

For more information, see  Engraving / Co2 laser section.

Conventional rubber stamps (matrix board)

It is necessary to have 

   - a laser or inkjet printer to print a film

  -  a photopolymer  machine to expose  and process  photopolymer plates, and get a cliche with  patterns in relief

  - a vulcanizing press (3 models available)  to press the photopopolymer plate into a matrix board and get a mold (patterns in  hollow), then to press rubber into the mold.

In case of rubber stamps, two manufacturing solutions are possible : laser engraved rubber or rubber molded in a matrix board. These two techniques are to be compared to photopolymer resin technique

Photopolymer liquid advantages

• faster processing  (25  -30 minutes).
• a single small sized machine necessary
• very low  equipment depreciation therefore low stamp cost price

Photopolymer liquid drawbacks

• ink restitution not so good  (polymer closed structure)
• resistance not so good over time
• resistance to alcohol-based inks not so good

Laser/conventional rubber advantages

• better resistance to inks (especially alcohol-based ones).
• more resistant over time
• better ink restitution  (rubber por
• choice of colors, nobler material.

Laser engraved rubber advantages

• Fast processing  (3 minutes 30 s) for a single stamp with a laser engraver

Conventional rubber advantages

• lower equipment cost, compared to laser
• Cost for  additional copies of a same stamp is very low and processing very fast : once the mold (with patterns in hollow) is obtained, only rubber is necessary and fast vulcanized.

Laser engraved rubber drawbacks

• high investment cost (laser engraver)
• long engraving time (2 hours 40 for A4 size, including  40 stamps, with a 30 w machine) that can be reduced using a  higher power laser tube.
• important maintenance :  90 % of rubber material need to be removed and release a lot of dust that dirty the machine.
• same work and same cost for additional copies of a same stamp

Conventional rubber drawbacks :

• longer processing time for the first  copy  (1 hour  10  for a 40 stamp A4 size)

Characteristics of 3 stamp types are summarized in the table below:

As a result:

Photopolymer stamps require low investment; their production is relatively economical and fast.

Conventional rubber stamps are interesting for large volume and additional copies of a same stamp (scrapbooking for instance)

Laser speed is interesting for small quantities, larger quantities requiring significant investment (100 w power). Also, it is important not to forget laser maintenance cost.