Eye Marks in Packaging - Technical Question

Question

I am a packaging Graphic Designer. I normally worked in packaging for homewares and some food but now working in beauty.

I have looked at all our different components and cannot figure out some details about eye marks. My understanding of eye marks are that they tell the machine where to cut or crimp the product. If this is correct should the eye mark hit the edge of the product? or should the eye mark hit the lower edge of the crimp? also does the eye mark height have anything to do with the size of the crimp? All the products I looked at were not consistent. See images below:

Any more technical info in regards to specifications and placement of eye marks would be great.

Thanks,

Answer 1

The eye mark indicates not where the cut will be, it indicates when to cut.

The optical sensor can be a few milimeters away from the cut itself. The sensor see the mark, the cuter cuts.

The manufacturer need to give you a specific template for the type of machine they have, and how they have it configurated.

Answer 2

The eye mark is there to tell the machine on the pack line where to cut the film. The packs are supplied on a continuous reel. The reel is fed into the packing machine which cuts off individual packs, folds them, seals the join (creating a tube), seals one end, fills them with product and then seals the other end. The eye mark doesn't have to be at the point where the cut occurs as the machinery can be set to cut at an offset from the eye mark. The eye mark has no bearing on the crimps or seals, it is strictly for cutting. As mentioned above, the position, size and colour of the eye mark is defined by the factory / packer and all of this info should be included on the cutter guide and print spec. Generally, the eye mark needs to be high contrast (dark on a light background or vice versa) and should sit in a clear 'track' that runs in the direction of the roll as it is fed into the packing machinery. This means that no variation in colour, logos, text etc can be in the eye mark track. Some printers will add the eye mark themselves before making plates and may even move elements and adapt the design for best results, but some will insist on the eye mark being correct and included in the supplied print ready artwork. More often than not, the position will be chosen so that it is hidden or covered on the final assembled pack, usually underneath the seal on the back of the pack.

Answer 3

When I have worked on this type of tube packaging the manufactures would add these marks to the artwork. Ask your factory or add your own clear, removable instructions.

Answer 4

All of the above is correct and incorrect. On intermittent motion machines The eye mark controls the "movement" of the film. Not the cut. The cut itself is done in exactly the same location every time. The movement of the film in relation to the cut is what the eye mark is for. Basically the machine program uses the eye mark to determine where to stop the film feed. Generally the program tells the eye to look for the mark between X and Y of a machine cycle. On intermittent motion machines the eye provides a signal to the program and it slows and stops the machine for the cut process. On continuous motion machines it normally times the rotation of the cutting knife to coincide with the programmed cut length.