Note: Descriptions are shown in the official language in which they were submitted.
MEllIOD A~D APPARATUS FOR ~AKI~iG A
h~Ei9~
Thls Invelntlon relato~ to eolding ~sterlAlc and, rore
partlcularly, to 3ethods and apparatus ror making a chareo usod lr,
~ormlng a flber relnrorcod part by noldlng techniqu3a.
roun~ Art
~ iber relnrorced pla3tle (FRP) par-t~ aro rlndlng lncreasln~
aeooptance lr. tho ~arketplace. F~P articlel~, also knoun a3 oo~posltc~,
onsrally lneluds a ro~ln m~xod ~lth ralnl~orcln6 rlhorD antl varlou3
ri11er~ Sbo gart 19 typlcally ~ado by colding a ehargo lnto tho sha~s
oS the dealrod part ~der heat ard pres3ure. Tho charge sproadg to rlll
the ~old oa~rlty and ths char~ ts ~aintainod in tl~e aold l`o:~ a s~lrslcient
perlod o~ tlme to allo~r the rs~lr. to eurs to rOr~ tho tirlsh~d p3rt.
J;Dong the attrlbutes Or co~pslto artlcles 13 that they are
~,eror~l ly ~lehtsrel6ht but ~hibit r~latively hlgh str3n8th
cbaraetorlatlcs. Tb3 stren~t~ Or the3e garts i9 due ln largo part to tbe
rein~orcing flb~r~ ~n the re~
~ he char~s coopo3itlon ~arles consldorably froe appllcatlon to
appllcatlon. Ono Or tho ~ost eor2~only used charges la kno~n aa 3heet
noldln6 cocpound ~S~C). SHC la typlcally nade by a oo~tlnuoua procos3
Ybereby relnrorclng rlber3 are applled to a pasto contalnlng a
tber~o3ettirg reain. ~bs rollovlng patent3 dl3clo3e such a ~othod Or
~aklng an SMC-llke char6~:
C.S. Patent No. 4,294,490 to ~loolrel issued
October 13, 1981;
U.S. Patent No. 4,294,639 to Woelfel et al
issued Oetober 13, 1981;
U. S. Patent No. 4,376,749 issued March 15, 1983
to Woeliel.
These patents, along with U.S. Patents Nos. 4,220,496 to Carle~
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et al and 4,220,497 to Carley (bo.h issued September 2, 1980),
also disclose a method of making a charge known.as XMC, a
trademark of P.P.G. Industries, Inc. Briefly, XMC compounds are
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made by NindlDg continuous flbers around a drum so as to achleve a
generally helical shaped configuration of tb0 flbers.
While XMC and SMC charges haYe gsnerally perrormed
satls~aotorily rOr most appllcations, the proces3es ror maklng thsm do
j~ not readily lend themselves to preclse control Or the fiber orientation
therein. This i8 especially true when lt is desired to orient the flbers
ln a nultiplicity Or diff erent, but precisely controlled, orlentations.
Bulk molding compound tBMC) and thick moldlng compound (TMC) are
conventionally used in transrer or in~ection molding processes. It 1~
often d0sirable to u3e riber reinforcement in BMC and TMC charges. Fiber
., rsirrorced BMC ls generally made by mixing the resln, f`lller and cut rasr
ribsr strands or bundle~ together in a mixer. Typically, the mixing i9
`accomplished by using two blades that rotate in opposite direction~
thereby providirg a kneading action. Unfortunately, thls mixlng actlon
can separate the lndiYidual fibers in the strand3 unless the mixing 19
oareru}ly controlled. Such degradation Or the strand lntegrlty can lead
to a 1099 of physlcal propertie3 of the molded part sinoe the ribers
provide a more erfiolent reinforcement ir they remain integrated a~
strands instead Or being separated into individual fiber filaments.
According to the present imention, contlnuous strands Or fiber
filiaments are impregnated with resin and then cut lnto segments of
prsdetermined lengths. Tie resin impregnated segments are collected
together to ~oxm a charge for molding a fiber reinforced part. In o~e
embodlment~ ths lmpregnated segmenti3 are c0112ct~d in a controllcd manner
80 that the segment3 are pil0d to~ether and lie ln a glven orientatloD.
Prer0rably, th~ impregnated strands are pulled by a rotating drum throu~
a res1n bath ~nd cut lnto segments ~ith a~ associated rotatlng cutt~r
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mechani.~m. The cut 3egments are allowed to fall lnto a receptacle which
has been formed lnto a shape generally correspondlng to the deslred shape
the charge. The receptacle can be moved relatlve to the falline
segment3 to change the preferred orlentatlon Or the rlbers into a
multlpllclty Or diPfcrent dlrectlons. For example, the receptacle can be
rotated 90 that the 3egments are all orlented ln es9entlally P radially
outwardly 0xtending dlrectlon.
Apparatus is made pursuant to this lnventlon that comprlsea fir3t
~eans for pulllng contlnuous strand3 of fiber rllaments through a resin
bath to thereby impregnate the strands ulth resin. Second means are
provlded for cuttlng the impregnated strands into segments of
~predetermined lengths, and, tblrd means operate to collect the segmcrt~
together to form a charge. In a particular cmbodlment, the thlrd means
operates to collect tbe segments in a controlled manner so tbat the
segments are plled together and lle ln a given orlentatlon.
` Pursuant to anotber feature of this inventlon, an i~proved
cutter mecbanism is provided.
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. i Brie~ ~escrlPtlon o~ thc DraNin~æ
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i~Varlous advantages o~ the present lnvention will become apparent
to the ski~lled practitioner upon a study of tbs specirlcation and by
reference to the drawlrgs ln which:
`~Flgure 1 18 a perspeotlve vlew Or apparatus used in carrying out
~hf~teachings Or the present lnvention;
~?', _, t .' . Figure Z ls a view sh w ing portlons Or the receptacle in cross
aotlor. b~eath the cutting mechanism for cutting the flber strands, and
`.-Flgure 3 i8 an ~nlarged cross-sectional vlew of portion3 Or the
:;outter mechanism.
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Do3crlptlon Or tba Prol errad ~mbodlme~
~ ersrrlng no- to tbo drawlngs,- a creel or raok 10 contsln3 a
"lur311ty or bobblns or packa~5a~ 12 o~ contl~uou~ rat.~ rlbsr strand~
Tbe otra~d~ 1~ oach oontaln u large pl~lrsllty Or lndividual ribsr
rllaYIcntY. JU~oDe 4ny ~lbor Jtrand~ 08~ be uagd iu tho pre3aDt lsveotlon
Yb~ch r~ulS~ ln ~ compo~lta Or h~8h ntronl;th ~nd ~blcb ~oa~a3~e~
~urtlolont Sen3110 ~tron8th to b0 ~ullad througb ths r~J31n bath 16.
~xa~plas Or ~trand5 tbat may bo utilized i~ thl~ lnYention ~re ztrallds o~
~oly~ d0 fiber~, ~olyostor ~lber~l polya~ids rib3rs, natur~ ~lber~ and
ni~tal ribers. Strand3 Or polyaran~da ribera, gla3s tl ber3 and carbor.
rlber3 ars prererred, llth gls9~ rlbera ~reaeDtly providlrg the best
re~ulta for ~03t appllcatlos ~.
TbB re31n ln batb 16 may be any naterlsl that proYlde~ the
neco3~ary bondlng asd stron8th ror the co~po~lte artlole rormed. I~ong
typical rea~na are polyara~idc3 and novalacs. Suitable re31ns ror the
lnatant proce~l sre lnyl eater~, epoxy resln~, polyurethaoes and
polye3ter3. Prererrad ro~is materlal~ ara tbGr~ally cured polyester
raslna. Bath 16 ~ay tal~e tho rorm Or eny 3ultable con3tructlon altbougb
A 3ubstantlally c~o~ad cell havlng ro31n reclrculatin~ tborcthrou8b 1~
presar~ly Drarerre~ a9 dl~clo3ed ~ n ~oro detail ln our U.S. Patent
No. 4,643,126, issued ~ehruary 17,1987 and entitled "Method and
Apparatus ~or Impregnating Fiber Strands."
~ ho oontlnuouJ raY ~Ib0r atrand3 1~ pa3s ~et~ean bar3 18, ~0 and
u ~et of adJuotabla eyGlet- or co~b3 22 beroro antorlng batb 16. lt
Dtart.u~, tb~ ends or strand3 1~ ira tbroaded througb ~aterlng orirlcea
26 asd pa~o underneath bar 28 Yhere the strand3 14 aro vrap~ad about tbll
arou~rerorce Or 8 dr_ 30. Dru~ 30 :~ oounted to a ~tand 32 adJaccnt a
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~econd rotati ng drum 34.
Drum 34 19 part Or a cutter mechanlsm generally desl~;nated by tho
n~eral 36. As can bo 3een mo9t clearly ln Figure 3, a slot 38 ls formed
ln the outer surface of drum 34 and extends parallel to lts axls of
rotatlon. A sprlng member 40 is mounted ln slot 38 30 that it extends
radially outwardly from drum 34; 1. e. transversely to the drum axis.
Prererably, sprlng member 40 takes the form Or a generally rectangular
planar 3heet of material which i8 relatively stiff when forces are
exerted a~ainst it ln the plane of tho sheet but 19 otber~ise compliant
lr. other dlrectlons. The degree o~ co~pllancy or r2siliency of spring 4Q
ln thess other dlreotlons can be easily controlled by the am~unt of
overlap of plates 42. 44. 46 and 48; a pair Or the plates being located
or. each slde Or sprlng 40. Spring 40 is a sheet o~ col~po3ite graphlte
materlal lr thls partlcular embodlment but other suitable sprlng
materials can be usad. Plates 42-48 are made Or steel in this
embodiment. Sprlng 40 and plates 42-48 are held ln slot 38 by a palr of
alongated holders 50, 52 which are compressed by a set screw 54. A
cutting head 56 ls fixed to the outer edge of sprlng 40. Cuttlng head 56
Is made of' tungsten carblde material in thi3 example and presents a
relatively sharp edge 5 8 for ¢uttl cB the straDds.
; In operatlor, means (not shown) are proYldod for rotatlng drum 30
ln a counteroioclcwlse direction ln synchronlsm with the rotatlon of drum
34 ~rhlch rotates in a clockwlse dlrectlon. The rotatlon of drum 30
oparate3 to pull the raw ~iber 3trands 14 through the resin bath 16 where
the strands become lmpregnated wlth rasln. The lmpregnatsd strands exit
bath 16 and pa39 through metering orlflces 26 which squoeg3e out e~cess
re sin.
As the impregnQtad strands 14 pass oY~r drum 30 they are cut lnto
se~ents 60 by the operatlon of cuttsr meohanis~ 36. The rela~ive
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rotatlonal speed between drum 34 and drum 30 determines the lengths Orthe indivldual segmentA 60. When the cuttlng edge 58 comes lnto contact
with drum 30 lt simul taneously sever~ the plurality oP strands 14
thereon. The sprlng 40 19 sufflclently oompllant 90 that lt wlll bend as
~hown ln Figura 2 durlng oontirued rotat'Lon of the drums. Thls permits a
good deal of latltude ln tho spaoln~ toleranoe between the outtlng head
56 and drum 30 slnoe the spring 40 wlll bend to oompensate for any
olrerlap. In addltion, thls construotlon tends to mirlml~e noise durlng
the operatlon and decreases down time which may otherwise be necessary to
adJust the outter head spacing when the ecge wears. The segment lengths
may vary as desired but at the yresent tlme segment lengths in the range
oP 0.25 - 2 inohes appear most praotical. Pre~erably, the segments 60
are out lnto lengths oP 0.75 to 1.50 inohes, wlth lengths oP about l inoh
belng mo~t preferred. Segment lengths ln excess of 2 irches flnd
dlPflculty in partlng from the drum 30 a$'ter they are cut. Segment
lengths less than 0.25 lnoh are dlff'ioult to obtain due to the Yery hi~sh
rotatlonal speed that would be required Prom cnttlng drum 34. Also.
aeg~ents smaller than thl3 are dlffioult to or~ent in a predetermlned
pattern.
The cut resin impregnated strands are then collected togethar ln
~r variety oP different ways to f`orm a charE~e for moldlng a fiber
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reir,Porced part. In tha partio~lar elDbodiment shown ln the dra~lng3, tbe
out-s~gments 60 are collected ln a oontrolled manner 90 that the segments
ars :piled together and lie ln a given orlentation. Thls 19 preferably
aqco~plished by way of a recepcaole that moves underneath the cutter
ani~n 36 in various directlons 90 as to control th~ orlentatlon of
the cut se8ments 60. ~hen the se3ments are cut and allowed to Pall ln
tho dlreotlon they are thrown from drum 30, thelr orientatlon is
~enerally parp~ndloular to the axis of the`~rotatlng drum3 30l 34, i. e.
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the cut 3e6ment3 SO gonerally remaln ln the same orlentation as the axes
of the strand~ 14 Prom whlch the see;ments are cut.
The swath of ths region onto ~rhlch tho segments 60 are deposlted
can be Yarisd by a varlety OI factors ~uch a3 the number of strands 1~
b~ln~ slmultan~ously cut, the latsral spacing therebetue0n, etc. ~or
exaQple, if the swath oP the deposlted reelon 19 to bs small, then a
fewer number of strands are 31multaneously out and/or eyelets or the like
to group the strand~ to~ether into a clo3er spacing before they are cut
may be used.
In the dra~lngs, the receptaole takss ths Porm oP a cup-shaped
dl30 62. Preferably, thq receptacls can moYe ln a variety of dlfPerent
dirsctlons co as to alter the orlentation of the cut segDents 60. In
this embodlmentj disc 62 19 capable oP rotating as well as belng movable
back and rorth ln a dlrectlon generally perpendlcular to the a~es Or the
rotatlng drums 30, 34. Rotatlon oP the disc 62 causes the cut segments
60 to lie es3entially in a radially outwardly extendlng dlrection.
Rotstlon Or dl3c 62 can be provided by a number of difrerent mechanisms
8uch as by way of` a motor 64. LikeN13e, the linsar Qovement oP disc
receptacle 62 can bs done in dlfferent ways. PrePerably, motor 64 19
oonneoted through a gsaring arrangement ~not sho~n) to drlve the vh~els
66 mounted on a traok 68. The llnear movement oP dl3c 62 controls the
thlckns~s oP the out 3egments that are deposited or radlally extending
rsgions o~ th~ charge belng formed. As shown in Flgure 2, it may, in
80me lnstances, bo tlesirable to have the center oP th~ charge thicker
than the perlphery thsreof. Thi3 can be easily accompllshed by kespinK
the cutter mechanl3m 36 abov~ the c0nter o~ the di~c 62 for a longer
psrlod of tlme than at the periphery tbereof.
Onc~ the dssired thlckne~3 Or the ch~rge has been aohieved, the
oharge can be removsd rrom ths reoeptacls and th0 resin alloved to
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partially thlcken or ~B-9tagen a3 thl9 i9 commonly rererred to ln the
art. It i~ eenerally advisable to llne the lnterlor Or the receptacle
fl ulth a releas~ sheet 70 to aid ln removlng the charge from the
receptacle. Generally, it is prefelable to allow the resln to partlally
1 thicken so that the charge can be more easily manipulated. Some
?, thicXening can occur before the charge is removed from the receptacle
and/or the charge may be placed ln an oven to more rapidly achleve thi3
~emi-solid state. After it i~ B-3taged, the charge is then ready to be
inserted, for e~ample, into a compre3sion mold for Porming at least a
portion oP the composite article.
i An alternative ~ethod is to collect the cut resin impregnated
.~, strands frcm cutter mechanism 36 in a hopper which feed3 lnto a transfer
or in~ection molding maohine. The impregnated strandA thus form a charge
whlch is typically Porced into the mold by way Or a ram or screw drive.
- J~ Hhile this method does not provlde the controlled fiber orientation as
does the method discussed above, it 3till i3 expected to proYide the part
~lth oxcellent reinforaement. This i9 becau~e the plural fi~er3 in each
~trand tend to remain together in the method Or thls invention and are
not separated a3 i3 the case in the conventional charge making proce3s
diacussed herein where mixing of raw (unimpregnated) strand3 with the
' ~7: rasin was required.
Fro~ the foragoine, lt can be appreclated that the present
lnvention enablss one to relati~ely easily produce a charge that ls
capable of provldlDg a part wlth excellent reinrorcement properties. If
- desired, aocurate control Or the orientation of the fiber3 in the charge
; can be obtained relatively easily and without substantial expen~e.
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Charges made ln sccordance ~ith this inventlon can be used Por formin3 a
~ide varlet~ of parts such as door3 with ~elective rsinforcement areas
therein, autc~otlYe parts such as panels, wheels, and the like; 9kis and
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almost sny other compo9ite artlcle where lt i8 advantageous to control
tha orientation o~ the relnforcin~ flbers thereln. The ~ull extent of
th~ contributlon to the art made by way Or this invention wlll become
apparent to tbe 3killed practitloner arter a 3tudy of the specirlcatlon,
drawings and claims.
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