BS/EN 4726-2018 pdf download.Aerospace series – Acceptance parameters of aesthetical variations for all visible equipment installed in aircraft cabins under all contractual variations.
b) In cases of split line production templates, the templates may also be used for quality inspection checks.
c) Split line necessity overrules aesthetic reasoning.
d) Parts with integrated deep recesses or 3D shapes surpass most technical solutions for films and therefore generally split lines shall be set or a different medium chosen.
e) Decorative Sheet Material (DSM) (formally known as PVF film) split lines are always overlapped by 10 mm (0.393 inch) and If wrapped around edges, e.g. doors, etc. shall also have a minimum of
10 mm (0.393 inch) wrap around. Reinforced material (DSM film) is always butt jointed.
1) All split lines in all mediums are optically straight, neat (no over spray by painting) and run parallel to edges, i.e. vertical or horizontal, unless otherwise defined. If a split line is noticeable to the eye, i.e. slanted It is considered a defect. Butt joint edges cover the substrate panel completely, I.e. nothing of the panel is visible through the butt joint.
g) Split lines are as a rule visible and are therefore so acceptable, although the goal is always to make them as least obvious as possible.
h) Split lines for Hydro Transfer Printing Technology (HTPT) have a different set of rules and can be found in the HTPT document.
I) Paint split lines whereby two different colours meet on a single part shall have a smooth transition. i.e. no noticeable (to the touch) paint depth difference at the edge (supplier to provide samples for acceptance).
j) DSM cut edges are never left exposed except when an overlap is defined.
k) Split lines that are not to the OEM interior colour specifications i.e. definitions are considered a defect and shall be re-worked.
4.5.3 Pattern alignment over two or more sheets/parts Pattern alignment over two or more sheets/parts are:
a) Pattern alignment refers generally to the printed decorative layer of a Decorative Sheet Material (DSM) film. Non-standard materials that are embossed, engraved, textile, natural products. imitations of natural products. suspended compounds and special effects or have a structured surfaces etc. shall be handled on a case by case method during the prototyping phase and thereby the parameters documented by the manufacturer and submitted to the OEM for validation.
perfect pattern alignment across two decor sheets is not possible due to these mechanical properties inherent in the manufacturing. However It is possible to align one control point within the pattern, this control point and the position thereof is defined in the appropriate OEM Interior Colour Specification (ICS), deviations from the ICS are regarded as defects and shall be reworked. Any DSM defined control point position has a tolerance of 2 mm, i.e. ±1 mm (0.079 inch ± 0.039 inch) on purely flat surfaces and on curved or wavy surfaces it is 4 mm, I.e. ±2 mm (0.158 inch ± 0.079 inch).
c) Symmetrical patterns whether produced by silk screen or digital will show a degree of ‘pattern warping” as already mentioned, this is inherent to the manufacturing process and is thereby not considered a cosmetic defect. The tolerances shall be assessed and agreed upon by the OEM and the manufacturer, latest at the material First Article Inspection (FAI). A full size actual production sheet is sent to the OEM for archiving and thereby a record of each agreement.
d) These rules apply in vertical and horizontal axis or in some unusual cases at a predefIned angle as listed in the appropriate OEM colour specifications. See pictorial and simplified examples in Figure 15 for basic rules about acceptance.
e) Unusual decors shall have their own additional set of rules, these shall be defined in the pertinent OEM interior colour specification for orientation or/and documentation of exception.
f) If pattern and/or texture alignment is good but the wrong formats have been used i.e. against definition, then the decors are still considered as a defect and shall be reworked by the supplier as a non-conformity.
g) Some decors will incur a pre-trimming to produce the control point needed for a serial solution. These preparation instructions/definitions although seemingly intensive are still mandatory as they secure a serial repetitiveness, failure to conform is a defect and shall be reworked by the supplier as a non-conformity.
h) Perfect pattern and/or texture alignment around corners (e.g. from the aisle across to the rear wall) and including integrated corner decoration strips is not possible.
i) Pattern and/or texture on moving, multi part walls e.g. aisle walls with doors – although “perfect” alignment can first be achieved by cutting the required parts from one full size sheet; after module installation and door/wall adjustments have concluded, the pattern alignment may be negatively influenced. This is not a reason for rejection. Only if it is obvious that multiple sheets/bits have been used or a rework on one part only took place and including the prerequisite the definition calls for one sheet to be used, then the decor will be considered as a non-conformity. Any subsequent replacement part introduced thereafter will negate any optimal alignment previously achieved and be regarded as a non-conformity.BS/EN 4726-2018 pdf download.