Note: Descriptions are shown in the official language in which they were submitted.
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METHOD OF MANUFACTURING A LINED MOULDED PART
The invention relates to a method of manufacturing a
laminated moulded part having a carrier portion and a lining
material and to a tool for carrying out this method.
Shaping of mixtures of polypropylene and wood particles is
known in the expert world by the title HMPP (wood flour
polypropylene). In this case the material mixture is
produced in panel form by extrusion (if necessary with
additional calenderingy, the wall thickness of the panels
corresponding to the thickness of the later moulded part.
These HMPP panels are heated, preferably by radiant heating,
to the softening temperature of the polypropylene, and
thereafter shaped to form the respectively required moulded
part by means of shaping processes known per se such as
vacuum deep-drawing, pressing in a tool comprising male and
female mould parts or the like. In this case the tool
temperatures lie below the softening temperature of the
polypropylene, so that the material cools during shaping and
the moulded part can be removed in a dimensionally stable
manner from the tool.
There is described in DE-OS 2~ 95 117 a method of producing
panel material, which may be pressed to form moulded parts,
of cellulose-containing material and at least one
thermoplastic binding agent, the cellulose-containing
material and the thermapl~st:ic binder being
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mixed, and the mixture being shaped into the panel
material in a heated condition. The method is
characterised in that the cellulose-containing material
is pulped to provide fibrous material. and mixed with
the thermoplastic binders, a fleece being formed from
the mixture and this fleece being compressed by the
action of heat and pressure to form ~>anel material.
The aim in this case is to propose a method which
permits the manufacture of panel material in a simple
and cost-effective way, which is characterised by good
homogeneity and mechanical properties, and which may be
subjected to final pressing in a simple way in order to
produce high-quality moulded parts.
Polyethylene, polypropylene, polyimide or the like may
be used as thermoplastic binders, conventionally with a
proportion by weight of more than 40'x, preferably 50 -
605. The high proportion of therrnopl.astic binders is
feasible for reasons of cost and technology (softening
temperature) in present prior art on1_y with. the use of
polypropylene. Subsequent lining of the moulded parts
in one working procedure along with shaping is the aim.
In this case however the lining cannot be unbent overdo
i.e. laid around the edge of the moulded part, a factor
which severely restricts the range of application of
the moulded parts, and thus also the range of
application of the method proposed, In DE-OS 28 45 117
the following statement is made regarding this problem:
~~a further advantageous possibility ~_onsists ir.
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connecting a surface layer, for example a film,
preferably a textile layer (fleec~, textile, knitted
fabric) with the moulded part before pressing. Because
of the proportion of thermoplastic plastics in the
moulded part, the surface layer is welded thereto
during pressing in one operation. TY~us such layers may
be directly laminated on to the moulded parts, or, for
example, a carpet may be pressed on. As heating of the
pressing tool is not necessary, and operation is
frequently carried out even with cold pressed tools,
the surface layer may be selected from an optional
number of types and may even comprise a thermoplastic
film, which would :immediately melt in a hot press
tool r~ .
Bending over during the one~shot process was regarded
as impossible for two reasons;
1. Trimming of a moulded part durin~~ or after pressing
and lamination had to be effected "oz-i the linings, as
an overhang of the lining is requires: for bending over;
in view of the normal manufacturing thickness
tolerances of the carrier portions, this was not
regarded as feasible, and
2. the previously necessary content of more than 50~
by weight of thermoplastic binders, rxbove all when
polypropylene is used as a ~.~inder, renders difficult
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adhesion of the bent-over portion of the edge by the action
of parting compounds.
Proceeding from this point the purpose underlying the
present invention is to indicate a method of the type
already described, by means of which bent-over lined moulded
parts may also be produced in the one-shat process, and to
indicate a mufti-function foal for carrying out the method.
In accordance with an embodiment: of. the present invention
there is provided a method of manufacturing a laminated
moulded part, comprising a dimensionally stable carrier
portion and, connected therewith on a visible side, a
decorative lining material, in which a heated blank of a
mat-shaped or panel-shaped semi-product comprising cellular
material containing binding agents is shaped in a cold tool
to form a carrier portion, and is simultaneously connected
to the lining layer, the method comprising the steps of:
inserting the lining material into a mufti-function tool
with an overhang relative to the contour of the carrier
portion, the lining material being clamped and secured
peripherally along the contour C>f the carrier portion such
that the overhang of the lining material is angled to a
surface position of an edge of the carri.~~r portion
inserting the heated mat-shaped or plate-shaped material of
the carrier portion into the mufti-function tool and shaping
by closing the tool, t~~e heated mat-shaped or plate-shaped
material of the carrier portion is connected in the region
of the surface of the moulded pardon with the lining
material, an overhang of the carrier portion material being
separated along the edge of the carrier portion by shearing;
trimming the overhang of lining material by a trimming
knife, which is integrated in the mufti-function tool, and
which is operated separately from the shearing of the
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overhang of the carrier portion materials removing the lined
carrier portion by opening the multi-function tool after
consolidation of the carrier portion; and bending over the
overhang of lining material around the edge of the moulded
portion in a separate tool.
In accordance with another embodiment of the present
invention there is provided in a method of manufacturing a
lined moulded part comprising a dimensionally stable carrier
portion and, connected therewith on a visible side, a
decorative lining, in which a heated blank of a mat-shaped
or plate-shaped semi-product of cellular materials
containing binding agents is shaped to form the carrier
portion in a cold tool, and is simultaneously connected to
the lining, and in which the carrier portion is trimmed in a
multi-function tool by means of shearing, and the lining is
trimmed by trimming knives, in such a way that the lining
forms an overhand which is capable of being bent over, the
improvement comprising the steps of: inserting the lining
material into the mult.i.-function tool with an averhang
relative to the contour of the carrier portion, and
peripherally clamping and securing along the contour of the
carrier portion in such a way that the overhang of lining is
angled to the surface position of the edge of the carrier
portion; and trimming the lining material by a trimming
knife integrated into the multi-function tool, and which is
operated separately.
By virtue of the fact that the bending-over overhang of the
lining material is clamped and secured after its insertion
into the multi-function tool, in such a way that it is
angled to the surface position of the carrier portion, i.e.,
peripherally along the contour of the caz~rier portion, this
region in which the carrier portion must be trimmed during
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its manufacture, remains accessible, and the overhang of the
lining remains protected. Use of a multi-function tool in
which the lining material and the mat-shaped or panel-shaped
semi-product is shaped and lined, and in which all trimming
procedures are carried out on sate without
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transfer, gives rise to the advantage of a perfect
adjustment of lining and carrier portion with specific
bending-over material, so that the subsequent bending-
over procedure may be effected in a mechanised manner.
The lining material in this case may be fed in as a raw
blank, but also in the form of a strip withdrawn from a
roll, in that case for example with the aid of clip
chains.
Feed of the heated mat-shaped or panel-shaped semi-
product for the carrier portion to be shaped may be
effected in the same way and in the subsequent process
Step in which the semi-produce is also shaped and
connected to the lining material. In this respect the
overhang of the carrier portion material is
peripherally trimmed, e.g. by a conventional cutting
edge (overrun cutter). Such a separating procedure is
on the one hand independent of any thickness tolerance
'~0 of the shaped carrier portion, and on the other hand
the shearing forces are fully supported on the lower
tool, and do not stress the bending-over overhang of
the lining. As the lateral region of the carrier
portion in the method according to the invention is
directly accessible, no constructive difficulties arise
in the design of the trimming cutting edge.
The third process step includes the final trimming of
the lining to the bending-over dimensions, by means of
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a rotating trimming knife which is integrated into the
mufti-function tool, and which may be operated
separately. The advantages of combination of all the
method steps up to the actual ~~bending-over9~ in a
single mufti-function tool have already been stated as
regards the overall outlay and tool and manufacturing
precision. zn a fourth method step, which terminates
the manufacture of the moulded part., the moulded part,
after it has cooled and has thus become dimensionally
stable, is removed from the mufti-function tool,
transferred into a conventional bending-over tool, in
which the overhang of the lining is adhered about the
edge of the moulded part (is bent aver).
Thus the method according to the invention enables
lined moulded parts to be produced in the one-shot
process in an advantageous way, and to be "bent-over~~
in a proven fashion, and at only a slight added
expenditure for the mufti-functian tool.
Separate lining using environmentally-unfriendly
solvents can be eliminated.
The method according to the invention can be
advantageously further developed in that the moulded
part may be provided with punched apertures
simultaneously with the bending-over procedure in the
bending-over tool, fox' example for door handles, ash-
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trays or similar components which are to be applied. Thus
transfer and manufacturing time can be economised.
In the case of complex shaping and/or sensitive lining
materials, these may be used in a pre-shaped form in areas
and/or by approximation. The range of application of the
method according to the invention can thus be considerably
extended. Lining materials which are capable of deep-
drawing may naturally also be pre-shaped directly in the
multi-function tool. fhe peripheral securing, after heating
the lining material in a known way, permits vacuum deep-
drawing directly in the mult.i-function tool, when its cavity
is designed to be evacuated, a feature which provides no
problems.
The application of additional components to the rear side,
such as clips and retainers, is possible along with the
shaping of the carrier portion. The adhesive attachment of
these components is possible either by means of binders
intrinsic to carrier portion or also by the use of auxiliary
adhesives, for example hot-melt adhesives.
An appropriate multi-function tanl for carrying out the
method usable in a vertical press, comprises a base plate 1
which is blocked stationary with the aid of the distance
sleeves 4 of the clamp ring ~, further comprising the lower
tool 6 which is movable with the aid of the lifting device
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towards the clamp ring 3, the lower gaol 6 including a
trimming knife, which may be aperated separately by
means of the lifting device.
It further comprises the head plate 2 with the upper
tool 5, the stroke-restricting stop means 12 and
centering bolts 10, the range of penetration (C in
Figure 5) of the upper tool 6 inta the clamp ring 3
being in the form of a cutting edge.
Such a construction is easily monitored and serviced.
Even vacuum deep-drawing of the lining material may be
integrated into this tool just as simply as transport
members, by means of which the lining and/or carrier
portion materials may be fed in strip form.
The invention is naw e~cplained and described in more
detail with references to Figures 1 - ~, which show:
Figures 1 - 6: the functional sequence in steps of the
multi-function tool in a cross-sectional view
through the lateral area of the tool;
Figures 4 - 6: according to an enlarged partial detail
of Figures 1 - 3, the shearing and trimming
sequence in the case of carrier portion and
lining.
In Figure 1 the base plate is indicated by 1., the top
plate by 2. With the aid of these plates, between
which all the components of thp mufti-function tool are
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located, the tool is clamped in a simply-operating
vertical press. Blocked stationary by means of
distance sleeves 4, there is the clamp ring 3, which
carries on its upper side the centering bolts 10 and
the stroke-restricting stop means 12, and which is
formed in the region "C" as a cutting edge. The lower
tool 6, which presents the visible side of the moulded
part, may be moved up and down with the aid of the
lifting device 11. The trimming knife 7, which is
movable up and down separately by the lifting device 8,
is an integral component of the lower tool 6; in its
inoperative position tshown in Figures 1 - 3) it
follows the lifting movements thereof.
The upper tool 5 is secured to the upper plate 2.
During the press stroke, its area "C" operates along
with the corresponding area of the clamp ring 3 as a
cutting edge for tximming the material of the carrier
portion 15. The arrows in Figure 1 indicate these
possible movements of the corresponding components.
Figure 1 shows the state of the tool after insertion of
the lining material 1~.
Figure 2, with the same nomenclature of the components,
shows how, by means of the upper movement of the lower
tool 6 in the direction of the arrow, the lining
material 1~ is clamped and ~;ecured between the clamp
ring 3 and lower tool 6, and the heated mat-shaped
material 15 far the carrier portion is inserted.
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Figure 3 shows the upper tool 5, moved by the press
stroke in the direction of the arrow into its final
position defined by the stops 12. The carrier portion
is shaped and lined on its visible side. The overhang
of the carrier portion material ~5~ is separated by
shearing; the bending-over trimming of the lining
material 14 has not yet been carried out.
Figures 4 - 6 are enlarged details of Figure 3, in
which are shown the shearing-off of the overhang of the
carrier portion material 15, and trimming of the lining
material 14. In this case the components are supplied
with the same numbers as in Figures 1 -3, and the
respective directions of movement are indicated by
arrows.
Figure 4 illustrates the start of the shearing
procedure in the carrier portion material 15, which has
not yet been shaped into the carrier portion. The
mutual operation of the cutting edges can be seen, and
also the fact that the bending-over region of the
lining material 14 is not mechanically stressed by the
shearing procedure.
In the illustration in Figure 5, the shearing procedure
is terminated, and the overhang 15' of the carrier
portion material 15 is separated. The semi-product 15
is shaped to form the Linished carrier portion 15'~
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(and finally compressed, as a semi-product capable of
compression form the basis of these illustrations).
Finally, Figure 6 shows the final tri~riming of the
lining material 15, by means of which the bending-over
area «B~~ is specifically shown, by means of the
downward movement o.f the trimming knife '7 in the
direction of the arrow. The trimming waste 1.4°, which
is not required, is in this case cut off.
Figures 1 - ~ explain a construction by way of example
of a multi-function tool according to the invention;
variations, for example the application of replaceable
cutting edges and cutting strips on the components 3
and 5, are likewise possible, as are different
geometries, by means of which the method according to
the invention may be realised.
