1. Introduction
  2. General
  3. Manufacturing of PK Sleeve

Manufacturing Process of PK Sleeve

The production process of PK Sleeves are similar to those of traditional paper cup sleeves, which including die making, printing, flute laminating, die cutting and gluing. But since the PK Sleeve involves the strength issue, therefore the material testing and the strength tests of final products are included in our standard process. Due to the existence of extra straps die line, the accuracy of above-mentioned process would need a much higher standard.

 

1. Material testing

Material testing includes : Grammage measurement, Water content, tension strength, tearing strength of the papers to be used. Papers will include the face liner and the flute plus base liner. And the Machine direction and Cross direction will be tested separately. The testing methods follow the specifications of ASTM.

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Material testing is important to us since the papers we are using may include many kinds of papers with a range of grammage such as kraft papers, white kraft papers, clay coated papers, etc. Since the papers are produced form Paper and Pulp Factories worldwide and same type of paper with the same grammage might present a quite different performance in the aspect of strength. We tested the tension and tear strength to make sure that the final products will eventually meet the set standard before the mass production process is started.

2. Die-Cut Making

A dieboard would consist of numbers of die module based on the size of the papers used. We will normally arrange as many as modules to lower down the cost. Unlike PK Sleeve, die-cut for traditional cup sleeve is relatively simple as picture shown below. As one can see, the dieboard is filled with ejection rubbers for PK sleeve. This is arising another problem. The cutting pressure would need to increase greatly in order to cut through the corrugated cardboard but when we do so the corrugated cardboard would be pressed too thin and the structure of flute medium would lose its major function - heat insulation. Therefore the control of the cutting pressure and the selection of the ejection rubbers are very important.

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3. Printing


It is advised that the design contents shown on PK Sleeve should notice that the existing of the straps dielines. The good thing is that PK Sleeves provide both sides as main printing sides unlike traditional cup sleeves which one side is for gluing joint and normally left for less important information.


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4. Flute Laminating

The corrugated medium is often 0.026 pounds per square foot (0.13 kg/m2) basis weight in the US; in the UK,
1c1ec9b34fa5a43f4b38098fb0d9dc47.JPGa 90 grams per square meter (0.018 lb/sq ft) fluting paper is common. At the single-facer, it is heated, moistened, and formed into a fluted pattern on geared wheels. This is joined to a flat linerboard with a starch based adhesive to form single face board. We then joined a second flat linerboard adhered on the top of the first linerboard to form single wall corrugated board (3 layers totally), by a laminator. The first Linerboard is recycled paper and the second linerboard (face liner) may be kraft papers, white kraft papers or other preprinted papers.

Common flute sizes are "A", "B", "C", "E" and "F" . Traditional cup sleeves normally use “E” flute. And this is also adopted for making PK Sleeves.


5. Die-cutting

Die-cutting for PK Sleeve involves a high level of attention to detail and meticulous still this is not easy to master. Die-cutting technicians will need to try several cuts and adjust the pressure for each module by adhesive tape.


PK Sleeve is sensitive to the thickness of the corrugated cardboard. If the pressure is too high it will press the cardboard too much and lower down the strength of the sleeves. Besides, a very thin cardboard cannot provide a good thermal insulation and lose the meaning of cup sleeves. On the other hand, if the pressure is way too low it will not cut thought the cardboard and cause lots of problems for later folding and gluing process or even cause difficulties to our users while tearing off the straps. Therefore, we will arrange different types of ejection rubber by locations to produce the ideal thickness of the products.



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6. Folding and Gluing

 

This is the final stage of PK Sleeves making. The standard Gluing machine would encounter difficulties if there is no adjustment made. The machine that we use is specially made for producing PK Sleeves only which folds and glues the sleeves accuate and fast.

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To further illustrate how the gluing machines fold and glue the PK Sleeve. We like to share a short film below. This is a test-run of gluing machine. The maximum speed of production can be up to 34,000 pieces per hour.