CA1339405C

CA1339405C - Bonding plastic and plastic matrix composite materials

Info

Publication number: CA1339405C
Application number: CA000606992A
Authority: CA
Inventors: Henry D. Swartz
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-07-28
Filing date: 1989-07-28
Publication date: 1997-09-02
Anticipated expiration: 2014-09-02
Also published as: JPH04502737A; WO1990000970A1; EP0427793A4; EP0427793A1

Abstract

Joining of thermoplastic parts (2, 4) of indeterminate thickness to each other is effected by application of heat to selected surface areas thereof (42, 44) by intense focussed infrared heat lines produced by parabolic-elliptical-reflection heat sources (22, 24) displaced by a reciprocating linear actuator (26), removable by a robotic controller (36) after completion of heating to enable intermediate pushing together of the parts by further actuators (32, 34) for bonding.

Description

1 3 ~ 9 ~ 5 ~i OF PIASTIC AMD PIASTIC M~RTx CoMPC61l~ MaISRIAIS

FIELD OF lNv~llc~/laL~hUUWU OF ~ lNV~NllUN

Ihe present invention relates to methods and a~ya~aL~s for the fuse melting or binding of plastic materials and plastic matrix ccmposite materials.
A composite is a resin or resin-like crystalline, amorpbous or sem1-crystalline matrix in which is embedded wires, fibers, whiskers or flakes typically of c~rhsn, graphite, fiberglass or boran. Reinforcing materials can be long, short, layered, ~ , orderly or randcm. Typically, layers cccposed of parallel fibers are oriented and laminated in dirre~
dlrP~t;~nc to p m duce a stress-free, l;ght~ ht, uniform sheet of unusual ~LL~
Reinforced polymer composites can maintain material strength and integrity at cont;nllollc source temperatures typically at 400 deg. F. and higher and have s~L~I~rl;~l usage in the fields of aircraft, automotive structures, construction materials, machine parts and a variety of ccnsu=er product ~t;~nc as a replacement for me*21 and wcod.
A major problem which has plA~l~P~ the plastic and plastic matrix composite industry is the lack of a~ iate ter~un~l~gy for joining of these composites. Present state-of-the-art bonding methods are unSa~;~r~ ; these ;nrll~P A~hPcives~
resistance welding, ultrasonic ho~;ng, vibration welding, ~ rt;~ bcnding, high frequency welding, mPrhA~;cAl fasteners and ilr~o~d radiant heat. Each method has i~t~ problems which this invP~t;~ cvcrco5e5.

- 13~9~5 It is an object of the invention to provide a quick and effective method of bonding plastic matrix composites and melt fusing monolithic thermoplastics and elastomers which overcomes virtually all of the problems inherent in present state-of-the-art bonding processes and results in bonds and fusions which consistently test in excess of 2,000 psi in lap shear, 1,000 psi or more in flat pull strength, and over 5 lbs. in peel.
It is a further object of this invention to provide a uniform bond which avoids the discontinuity introduced by adhesives; avoids the vibration and tearing inherent in ultrasonic bonding; avoids the ferrous residue inherent in induction bonding; avoids the thinning and weakening produced by high frequency welding; solves the problem of material puncture which is a problem with mechanical fastening; and eliminates the installation of high resistance wire that remains in the seam during resistance welding.
It is an object of this invention to provide a strong, stress-free bond of any geometric configuration.
It is an object of this invention to provide a leak-proof homogenous bond line without any reduction of the composite sheet's or part's thickness by means of molecular bonding within the resin of the joined thermoplastic composites such that the bond is as strong as the resin itself.
It is a further object of this invention to provide a method of bringing together the surfaces to be bonded immediately on the cessation of heating which result in bond strengths up to and in excess of 2,000 psi in lap shear on a l"xl" bond line, and over 1339~05 1,000 psi in a flat tensile pull, and more than 5 lbs in a test peel on the same l"xl" bond specimen.
It is a further object of this invention to provide non-contact heating of bond line material without reducing the thickness of the pre-joined sheets or parts in substantially reduced times of approximately 30 seconds to 10 minutes.
It is a further object of this invention to provide intermittent focused radiant heat means to both surfaces to be bonded prior to bonding and to provide heat means to the enriching matrix prior to bonding whereby only the outermost layers of the designated bonding areas on surfaces to be bonded are heated, leaving the internal temperature and fiber structure of the material essentially unaffected, and leaving the adjacent surface material unheated.

SUMMARY OF THE INVENTION

According to the invention, intermittent focussed infrared radiant energy is focussed simultaneously on the designated bonding areas on surfaces of multiple parts to be joined. A bonding agent consisting of a "neat" layer (i.e., essentially free of reinforcement or other foreign infusion) of the matrix material may be applied to one or both designated areas of the surfaces to be bonded. The surfaces are then brought into immediate bonding contact with sufficient pressure to accomplish the bonding without distorting the material.
The steps to accomplish the bonding are as follows:

1~394~

Step One: Abrade or clean (e.g. with solvent) the bonding areas to be jointed (optional) and/or enrich the bonding areas with a "neat" layer of thermoplastic resin, compatible with the matrix of each part.
Step Two: Apply with heat a pellet of neat resin or an extruded monolithic tape of neat resin to the bond line of one or both bonding surface areas of each interface of the material to be bonded.
(Alternatively, the resin tape may contain dispersed fibers or other reinforcement in some embodiments).
Step Three: Heat the tape (if any) and bonding area quickly without heating the inner layers of the plastic matrix material.
Step Four: As soon as the upper and lower interfaces and bonding tapes or pellets have been softened sufficiently to be reformed as a single fusion, the press is brought together quickly. A
mechanical stop prevents the upper and lower press parts from crushing the material; however, sufficient pressure between 10 psi and 300 psi is applied to provide the pressure necessary to fuse the bonding material together.
Other objects, features and advantages of the invention will appear from the following detailed description of preferred embodiments thereof, reference being made to the accompanying drawing, in which:

BRIEF DESCRIPTION OF THE DRAWING

Fig. la is a schematic vertical cross section showing a preferred method and apparatus according to the invention of heating the bonding 1339~5 matrix in the bonding zones by means of a robotically activated, reciprocating, non-contact, focussed, intense, infrared heat source disposed between the two press parts.
FIG. lb is a schematic prospective view of FIG. la.
FIG. 2 is a schematic view of the press parts being brought together immediately after the heating cycle with sufficient pressure, typically between 20 psi and 300 psi, to accomplish the bonding.
FIG. 3 is a schematic vertical cross section taken transverse to the materials to be bonded showing the advantage of using a non-fibrous, neat, monolithic thermoplastic resin to enhance the bonding area.
FIG. 4 shows a schematic view of a preferred manner of applying an extruded monolithic tape of the same matrix resin on the bond line of each interface of the joining sheets or parts.
FIG. 5 is an alternative embodiment of FIG.

3 showing the application of a preferred tape directly from an extruder onto the sheet or formed part to be bonded.
FIG. 6 is a schematic vertical cross section taken transverse to the materials to be bonded showing an optional method of abrading the fusion side of the bonding areas prior to heating.
FIG. 7 is a schematic vertical cross section showing a preferred method and apparatus according to the invention illustrating the stepped increase in surface temperature of the bonding zone with each stroke of the focussed infrared heat source.
FIG. 8a through 8e are schematic cross sections showing a sample of the wide variety of joint configurations possible with this invention.

- 6 13~ S

FIG. 9a, 9b and 9c are schematic vertical cross sections showing joint configurations of various multi-dimensional structures.
FIG. 10 is a schematic vertical cross-sectional view of the robotic arm with affixedparabolic elliptical infrared reflectors illustrating adjustment of the focal lengths of said heat sources.
FIG. 11 is a schematic perspective view illustrating the use of this invention for fusing parts of pre-molded elastomeric or composite thermoplastics.
FIGs. 12 and 12a are schematic vertical cross-sectional views of point focus parabolic elliptical infrared heat sources mounted back to back on a robotic arm which can be preprogrammed to trace on a circular or elliptical path.
FIGs. 13a, 13b and 13 are alternate embodiments of this invention showing the use of focussed parabolic elliptical infrared spot beams at various angles mounted on a robotic armature which can be programmed to move in any geometric configuration.
FIGs. 14-15 and 17 are schematic representations of another preferred embodiment at various positions of operation, as described.
FIG. 16 is a temperature-time trace applicable to operation of the FIGS. 14-15 and 17 apparatus.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
There is shown in FIG. 1 an apparatus 10, according to a preferred embodiment of the present invention for bonding two thermoplastic objects, comprising press platens, 12 and 14, heating means, 22 13~3~

and 24, mounted on a robotic armature, 26, the respective support and activating means, 32, 34 and 36.
The timing and closure pressure of the press is controlled by the press. Plastic materials to be bonded, 2 and 4, are affixed to the respective press platens by vacuum suction devices (not shown) integral to the platens.
During the heating phase the press remains in its open position. When the heating cycle is complete, the upper and lower press parts are brought quickly and forcefully together into the closed position, as shown in FIG. 2.
The heating sources 22 and 24, fixedly mounted on the robotic arm 26, are movable into or out of a work zone between parts 12 and 14, and are capable of reciprocal and pivotable movement within such zone. Each of the heat sources 22 and 24 are elongated perpendicularly to the cross-sectional plane shown in FIG. 1.
The focal vector of the upper heat source 22 is pointed upward essentially normal to the surface of the first plastic material 2 to be heated. The focal vector of the lower heat source 24 is pointed downward essentially normal to said second plastic material 4 to be heated. The heat sources 22 and 24 consist of commercially available parabolic/elliptical infrared lamps. The displacement, velocity, periodicity, temperature and focal lengths and path of said heat sources are independently controlled.
Prior to the heating of the plastic materials to be bonded, 2 and 4, bonding zones 42 and 44 of said materials to be fused are enriched with resin identical to the resin which forms the matrix of 1339~0~

the thermoplastic composite FIG. 3). To accomplish the placing of the resin enrichment pellet 50 or tape 52 which must be preheated prior to the heating of the plastic matrix composite materials, a robotic feeding arm is utilized (not shown). In alternative embodiments, extruded monolithic tape 52 is applied, as shown in FIG. 4, or preformed tape 54 is applied directly by an extruder (FIG. 5). An optional step, as shown in FIG. 6, is the abrading of the surfaces to be joined.
The incremental temperature of the surfaces of the bonding zones increases 80 with each stroke 82 of the reciprocating robotic armature with affixed, focussed heat sources, as shown in FIG. 7. Because plastic has a low coefficient of heat conductivity, during each brief cooling phase 84 of the oscillating focussed heat application the heat is radiated away from the surface to the air rather than to the interior material. Thus the internal temperature 86 remains virtually unaffected while the surface temperature increases to the melt fusion point as shown at 88 in FIG. 7. It is this alternative "endothermic/exothermic" process which is essential to the present invention. Alternatively, the heat sources can remain stationary and the materials can be reciprocated.
A multitude of joint configures is possible, as shown in FIGS. 8a through 8e. Three-dimensional preformed plastic objects can be bonded together as shown in FIGS. 9a, 9b and 9c. For example, any size corrugated board may be constructed by bonding flat sheets on either side of a stamp pressed board, as shown in FIG. 9c.

9 1333~

The focal lengths of the lamps can be adjusted to coincide with the surface of the material to be heated as shown in FIG. 10. This means that the heat is at maximum intensity at the bonding zone.
Indeed, if such intense heat were applied continuously, the plastic would melt or burn.
In an alternative embodiment this invention can be used to melt-fuse two halves of a preformed bulb as shown in FIG. 11. The two lamps 22 and 24 are mounted back to back on the reciprocating robotic armature 26 while the halves of the preformed elastomeric bulb 60 and 62 are placed on the upper and lower press parts 12 and 14. The focussed heaters 22 and 24 are then reciprocated and when the melt fusion temperature is reached, the robotic arm is removed and the two press parts 12 and 14 brought together. The result is a completely fused bulb 64.
In an alternative embodiment the heat sources are point-focus, parabolic elliptical, infrared reflectors 70, 72 mounted back to back on a robotic armature 26 which rotates in a circle or ellipse thus tracing out a circular or elliptical path on the materials to be bonded, as shown in FIG. 12.
This embodiment allows the intermittency of heat application to be accomplished not by a reciprocating back and forth motion, but by a continuous cycle which touches any given point on its path only once in every revolution.
In an additional preferred embodiment the robotic arm 26 with affixed, focussed heat sources 70, 74 can be computer controlled and preprogrammed to trace out any path, thus enabling a variety of 1 3 ~ S

geometri~lly Ch~F~ bonds to be acoomplich~, as shcwn in FIGS.
13a and 13b. This em}x~l~hent gives a fl~y;h;l;ty of application to this invention which far ~Yrep~c not only the reci~ w aLing armature, but also surpasses any bonding machine in the prior art.
In each embodiment the geometric paths, ements, velocities, periodicities, t~.~a~res, focal lengths and duration of heating of the heat sources are controlled by electr~nic circuitry which can be ~ uy~ammed by the operation by means of the control panel, not chown.
FIGS. 14-15 shcws a sy_tem more or l~CC as in the previcu_ c~ci~-c, with certain e~h~r~ L~. It includes press platens 12 and 14, mounting parts 2 and 4 to be joined, IR
heaters 22 and 24 mounted on a reci~L~aLing arm 26 of a rcbot machine 36. IR sensing units 122 and 124 are mounted on the IR
heaters and have ~L~ ve temperature control and power contr~l systems, TC and PC (both per se oonventional) to oontrol platen positions, reci~L~aLiQn rate and IR heating temperatures and times. Through this loop oontrol, based on monitoring the temperature of matrix resin on each of the a~ ls partC 2 and 4, ~LU~e~S paraae*erL are tuned to variable conditions of the materials to be joined. The sensint units 122 and 124 oontinuously read the rising temperatures of the ~ L;ve interfa oe bond line zones and send ~;grAlC back to the lamp (22, 24) power oontrols to i~ ase or de~Lease lamp power, U~
varying lamp intensity and projected radiation until both ;,~P;r~ oe temperature r~4~ints match. When the ~a~ ed fusion temperA~lre of each ma~rial's surfa oe is ~ , the c~ J~
signal the lo~t~ to shut off, the robot arm 26 to withdraw, and the press (32, 34) to cycle.
Ihe C~ eL~ a of the lines in the temperaturertime trace of FIG. 16 ~n~c~tes t~hat the upper and lower part ~ temperatures have L.~ ~.~l f~ ol;~Ation temQerature, which s;~n~lc the rem~val of t'he robotic arm. Thus, the 1~9~5 temperature of the matrix resin is taken on a oantinucus, ~ La~t basis and is used to precisely c~AlL ~l the overall welding cycle.
m e heating wavelength of the lamps is approxImately 1.1 microns; the optical s*~o~ have a ~e~al ~ e of 8.0 to 14.0mucrons, which blinds them to v;c;hl~ light. RFC~I1CP the ambient air may be very hot, the s~ o~ may be providad witn an air cooling jacket. Alternatively, each s~ can be located outside the heat area and mounted so that its optical lens faces ~r~ ly positioned right angle mirrors.
High-t~n~c~-~ture thermoplastics and thermoplastic com-posites tend to cool rapidly. It is eqcPntiA~ ce~, that the press holding the parts have a rapid dowl,~Loke of at least one foot per cec~r~. To prevent ~Ple~prious efre~ on the joint ~L~a~e~ by hi~ s~ure impact of the adherends, the press ut;l;~c a ~lhl P-downstroke function, as s~cwn in FIGS. 17A, 17B, 17C. Ihe press first closes at high s~eed to a ~Plpration zone, which is about one half inch from material s~rfa oe. Then final pressure is Ar~ on a ~pcplprated bas~s to a die stop.
FIG. 15 shows that parts 2A and 4A oomprising layered quasi-isotropic oomposite panels (the cross-s~c~;~ns of which are P~ praLed) ~ay have faoe layers 22 and 42 which are l~r~lly reconsolidated. FIG. 15 also indicates the reciprocating movement (arrow A, dark line and phantom end positions. FIGS.
14-15 also show the parAhnl;c/elliptical focus of the heaL~L~
rP~ e~t;ve portion at points on layers 22, 42.
Adaptable to dem~n~;n~ applications in the aerospAcP/aircraft, automotive, me~;c~l, and other market sectors, the process accomodates simple and complex joint C~f;~lrAt;~nR~ lt~;n~ spot welds, U ~_ limensional welds, and C~rt;~U~lC welds.
~ h;s inNP~ has been prA~;rF~ to achieve cu~ ~ing weld ~LL~ ~ U ~ with 1~ a~ PPring thermoplastic mater;~l~ of ~;g~f;~At~t military and commerc;al utility uses.

39~5 These materials include glass-, carbon-, and aramid-fiber reir~ d poly~U~U~erketone (PE~, polyphenylene ~11 f;~
(PPS), polya~ P (PAI), polyetherimide (~ 1), polyarylate, polysulfones, thermoplastic polymldes, and 1;~ crystal polymer (LCP ' s) .
ll~r~ ctic c~rncites (TPC's) for hi~l ~e~Lo~
applications generally consist of a high-performance theremoplastic matrix resin rei~o~e~ with fibers of ~d~Lul~, graphite, fiberglass, or aramld. Some matrix resins used in TPC's-are c~p~hle of oontinuous servi oe at 350' F to 700'F. m ey include ~K, PPS, PEI, PES, PAI, and cth~h~s. m e reinLo~tments are usually continucus and parallel or lamina~ed in different directions to provide a stress-free, lightweight sheet of unNsual L~Ll~.
m e potential performance and economic benefits of thermoplastics vis-a-vis thermosets in advanced composite ~pli~Ations has been well documented and ; n~ e lower-cost manllfA~lring, ir~f;n;te ~ Y~y stability, ~ f~ h;l;ty of flat sheet stock r~e~ocessing to correct flaws and effect repalrC~ ra~Le~ ~LU~ g cycles, high to~ s, and easier quality oontrol. Most of these a~ L5y~ are due to the fact that unlike thermosets, which are infusible and cannot be soL~ ~ by heating once cured into shape, thermoplastics become more viscous and flow when subjected to heat. m is characteristic makes thermoplastics ~ hle and facilitates the elimination of A~hP~q;ves and ~r~ ;c~l fasteners, koth of which are less than desirable for high-performance structural ~rl;~A~ C. See, ~ ~2~, et al., ~ c For fusion R~n~;n~
ThermoplAct~F Co~po6ites", SAMPE Qyarterly Vol. 18, No. 1 (Oct.
1986).
m ere are many problems applying these tradit~O~Al thermqplastic welding nk~l~ils to hi~. ~t~u~nance TPC~8 Such as APC-2 rArh~n fiber re~L~oL~d ~kK or Ryton PFS oomposites, which are LoLy~ie~ for ~rrl~cAticns that may require ~oints that are as 4 ~ 5 ~LL~1~ as the composite itself. TPc laminates oomprise up to seventy wt.% of reinforcement. While the introduction of reinforcing fibers into a matrix dramatically upgrades the physical ~,uL~ies of the c~Y~C;te, it often makes welding more ~;ff;~1lt since there is less resin avA;lAhle to melt and LeC~ nl ;~te into a fused joint. Reducing the amount of reil~oL~ment may i~Y~e wel~Ah;l;ty, but only at the ~'~L~ CP
of cr~s;te ~L~ ~ Ul. Also, the a~cu~31 1~ LIlA~tiss us~d as matrix resins in T~c's m~st be ~Lu~ se~l at higher temperatNres and have rui~n~er Il~L~ c;~ win~ s" than ccmmLdity and general purpose en~;nPering resins. Ihis denands extremely precise control of welding variables - par~ Arly the amcunt and time of heat to achieve optimum joints. Welding m~U~s such as induction, resistance, ultrasonics, and others that involve preclamping of parts before the intr~ ~t;~ of hect do not readily facilitate the direct sensing and mea~urement of joint melt temperatures without the embedment of thermao~ ~ or sensors in the joint area, a possible negative in many Arrl;cAtions- ~he ~h~ invention avoids these ~;ff; ~11 ties.
m e basic ~LW~S steps used to join high ~e~LuLmance TPC's using focused i~Lo~d melt fusion are as follows:
Surfaoe preparation: good wetting of a clean, rple~c~
agent-free, bond line is essential. ~l~An;~g ~oll~;~ns or plasma treat~ t is preferable to sanding or abrading the surfaoe, which may remove resin in the two facing a~ ~ plies and loosen the fibers. Ihe high temperatures of the fo~lce~ IR reci~,u~aLing beams (up to 1,200'F) tend to burn off surfa oe contaminants that may be LL~ in asperites of the interfaoe layers.
Posit;~n;n~ of parts into press: two parts are rl~e~
into upper and lower h~ fixtures in a suitable press. m e facing parts are held in oQen position durLng the heating stage.
Pn~ Ation of matrix tape t~p~;or~l): A fiber-free tape of film or resin may be ~r~ to one part surfa oe (the tape is chemically and thermally compatible with the matrix resin 1 3 ~

of the composite; a resin-rich surfa oe on the cr~pocite S~a~S
may elimlnate the need for this step). Au~U~r variable that may enhance weld ~L~-yLh is to have the graphite fibers in u m directional orientation in the first interface layers of each adherend.
Setting of welding parameters: Surface melt temperature gfals for each a~ ~ are set on two temperature controllers; the press cycle time, robotic stroke distan oe, and speed are set.
When the start button is ~#~3~, the robot will move the fo~lcP~ ir~cL~ heating lamps into the cpen press area and cxl:l3~ce horizontal reci~L~a~ion over the bond lines. during the reci~ aLion stage, the l~o illuminate ;mme~;ately on the first stroke and remain on while the np~r~l S~SUL~ read the rising surfa oe temppr~lre of each interfa oe . The Sk~e~u~ sign21 the lamps' power controls to i~ ase or U~Lle down each lamp's ;nt~C;ty until both ifiterfa oe temperature ~L~rints match. At this point, the s~ ~ signal the robot to remove the lamp fixtures fm m the press and start the dowl~LL~ ~ of the press for completing the aperation. the press remains olq~e~
until the part ccols ~lff;~.;P~tly for removal and h~n~
The focal ~e~L of the upper heat sour oe is pointed u~h~nd; the focal ~e~u~ of the lower heat scur oe is pointed dkqnb~lnd. To limit peroolation in the la~ m ates (which can cause interlam~inar slippAge, separation of fibers, and matrix ~;C~rt;n~)~ the parts to be joined are held as close to the focal Vt~ of the lamp fixtures as ~Y~R;hl~.
During the reci~ aLion stage the surfa oe temperature of hoth akn~ int~L~ac~B il~L~aSeB with each aLL~~e of the robotic arm. Rec~llRe the plastic has a relatively low coPff;~;Pnt of heat a~-7~;vity, during each brief cool;~ pbase heat r~ t~R away fram the surface to the air LaU~ than to interior layers of the composite. Thus, the ;r~rl~l temper~lre remains virtually unaffected while the surface ten4~eLaL~re 1339~05 i~L~2SeS to the melt n~ point.
If the fo~lc4~ illrLar~ heat lam.~s were stationary over the a~ ~~s at these high temperatures the matrix resin would burn im~ediately. However, the bean is m~ving and not in any one place long enough to cause b~u~l~ng. During the reci~o~ion of the lam~s the material of each adherend ~ ~e~es an Ar~el~rated exothermic reaction, that is, a chemir~l change in which there is a liberation of heat, and an endothermic r~A~tin~ that is, a rh~m;cAl change in ~hich there is an absorption of heat. It is the periodicy of the intensely fo~lcP~ moving beams that creates a faster growth of temperature at just the i~ Lrace~ of each a~ ~ his alternate "~ ~k~P~mic/eYx*~l3rmic" ~LU~S iS a unique aspect of fo~l-ce~ infrared melt fusion.
Bond lines up to s;Yte~n inches long and four inches wide have been prQ~lcP~ and it is EYy~c;hle to prcduce much larger bond line areas. Bond line length is controlled by the length of the fo~lRP~ infrared lamp6, which are commercially available up to one l~w~a~ inches long. The reci~lu~aLion zone controls bond line width. Very wide bcnd lines are E~Y~c;hle by using multiple lamp fixtures that are ~ side-by-side on the rnhot;c arms.
For example, four sets of back ~o ~0~ forty eight inch foQlcP~
infrared lamps ~F~re~ four inches apart can be used to heat a bond line area twenty inches wide by forty eight inches long.

Claims

1. A method of bonding monolithic plastic and/or plastic-matrix-composite materials reinforced with strength and/or stiffening enhancing agents comprising the steps of:
(a) providing selected bonding zones on the surfaces of the materials to be jointed essentially free of the reinforcing agent;
(b) briefly and repeatedly applying adjacent points or series of points of intense heat to surfaces of the materials in said designated bonding zones thereof to thereby effectively fill selected and limited areas of bonding zones with heat;
(c) continuously displacing the points or series of points of intense heat through the bonding areas in an intermittent, repeated motion;
(d) terminating the heat application and immediately bringing the heated areas into bonding contact before substantial cooling thereof, the said steps being controlled to produce at said heated surfaces temperatures in excess of respective melt fusion temperatures while areas away from and internal to said designated bonding zones remain substantially below such temperatures and effecting the bonding before the surface temperatures at said zones decline to below melt fusion temperatures.

2. A method in accordance with claim 1 wherein said bonding zones are enriched with additional plastic material essentially free of reinforcement.

3. A method in accordance with claim 1 wherein said bonding zones are overlaid by resin tape.

4. A method in accordance with claim 3 wherein the resin tape is preheated prior to placement at a bonding zone.

5. A method in accordance with claim 1 wherein said adjacent lines or points of intense heat are produced by focussed radiant heat.

6. A method in accordance with claim 5 wherein said focused radiant heat is produced by parabolic elliptical reflection which concentrates heat at one or more focal points wherein said focal points may be adjusted to coincide with the surface of the material to be heated.

7. A method in accordance with claim 1 wherein said adjacent lines or points of intense focussed radiant heat means are intermittently and repeatedly applied to said bonding zones.

8. A method in accordance with claim 7 wherein said adjacent intermittent lines or points of intense focused heat comprise reciprocably oscillating focussed radiant heat sources which are oscillated back and forth across the said respective designated bonding zones at preselected velocities with a preselected periodicity.

9. A method in accordance with claim 8 wherein the lateral displacement (i.e., stroke lengths) of the reciprocably operable radiant heat sources can be individually controlled.

10. A method in accordance with claim 1 wherein the temperature of said radiant heat sources at the respective focal points can be independently controlled.

11. A method in accordance with claim 1 wherein said moving lines or points focussed heat can be reciprocated in directions essentially oblique to each other.

12. A method in accordance with claim 1 in which said moving focussed points or line of heat can be rotated in any configuration.

13. A method in accordance with claim 1 in which the said path of moving focussed points or lines of heat can be controlled to trace out any preselected geometric path.

14. A method in accordance with claim 13 in which the path of said moving focussed points or lines of heat can be controlled to trace out any geometric planar surface, whether curved or flat.

15. A method in accordance with claim 1 wherein the said bonding zones define any chosen two-dimensional geometric configuration in three-dimensional space.

16. Apparatus for bonding plastic resin and plastic or resin-like materials reinforced with strength and/or stiffening enhancing agents comprising:
(a) a press comprising a first press part and a second press part with pressure applying surface s movable between a first open position with space between the two press surfaces and a second closed position wherein the two press surfaces bearing the two are resin or resin-like thermoplastic objects to be bonded are brought together;
(b) means for attaching the first resin or resin-like object to be bonded to the first press part and attaching the second resin or resin-like object to be bonded to the second press part;
(c) means for establishing bonding zones on the surfaces to be bonded;
(d) means for applying enriching matrix to said bonding zones;
(e) means for simultaneously repeatedly applying brief and adjacent lines of intense heat to the facing surfaces of the materials to be bonded;
(f) means for controlling the frequency of intermittency, the duration, and the area of the applied intense intermittent heat in said bonding zones;
(g) means for pivotably removing said robotic armature and said heat source means from the space between said first and second press parts;
(h) means for immediately bringing the heated surfaces of the materials to be bonded together before substantial cooling thereof.

17. Apparatus in accordance with claim 16 wherein said heat means are mounted on an armature pivotably movable between the first and second press parts.

18. Apparatus in accordance with claim 16 wherein said heat means are mounted on said armature oriented so that their respective focal vectors point in opposite directions.

19. Apparatus in accordance with claim 16 wherein said intermittent intense heat means comprise infrared parabolic elliptical reflector lamps mounted on moving shuttles which oscillate the lamps back and forth in a direction essentially Lateral to the surface to be bonded.

20. Apparatus in accordance with claim 16 wherein the focal length, displacement, oscillation period and temperature, velocity and length of total heating cycle of each heat lamp is independently controlled.

21. Apparatus in accordance with claim 16 wherein said heat means which produces said points or series of point (lines) of intense heat can be reciprocated in directions essentially lateral to each other.

22. Apparatus in accordance with claim 16 in which said focussed heat means can he repeatedly moved in preselected paths to produce any configuration of points or series of points of intense heat on the surfaces of the designated bonding areas having any two-dimensional geometric shape.

23. Apparatus in accordance with claim 21 and wherein the focal length, path, frequency of intermittency, velocity, period, temperature and total length of heating cycle of each heat source is independently controlled.

24. Apparatus in accordance with claim 16 wherein said first and second material to be bonded are attached to said respective first and second press parts by vacuum means.

25. Apparatus in accordance with claim 16 wherein said first and second material to be bonded are attached to said respective first and second press parts by mechanical means.

26. Apparatus in accordance with claim 1 wherein electrical switching circuitry is provided to effectively activate and control:
(1) the electric motors which control motion of the shuttles and/or moving armatures carrying the heat sources;
(2) the timing and initial opening and closing of the electric motors which effectivate the press parts;
(3) the voltage and current through the heat lamp;
(4) the electric motors which control position and focal point of the heat lamp relative to the bonding zones;
(5) the electric motor which effectivate timing, position and motion of the robotic armature.

27. Apparatus in accordance with claim 16 wherein computer means is provided to effectively preprogram and control the path, periodicity, velocity, focal length, temperature and length of time of the heating cycle.

28. Apparatus in accordance with claims 16 wherein computer means is provided to effectively preprogram the motion of the robotic armature and the opening and closing of the press parts.

29. In the method of bonding parts of indeterminate thickness of monolithic plastic and/or plastic-matrix-composite materials reinforced with strength and/or stiffening enhancing agents, the improvements comprising the steps of:
(a) effecting a temperature rise at each of selected surface areas of the parts to be joined by cyclic application of intense, focussed, infrared radiant heat to surfaces of the materials in said selected areas to establish a stepped rise of temperature essentially limited to said selected surface areas, with each of several steps comprising a rise portion and a decline portion until melt fusion temperature is achieved; and (b) then terminating the heat application and immediately bringing the parts together to place said surface areas thereof into bonding contact before substantial cooling thereof.

30. A method in accordance with claim 29 wherein said focussed radiant heat is produced by parabolic elliptical reflection which concentrates heat at one or more lines of cross-section focussed at the part surfaces.

31. Apparatus for practice of the method of claim 30 comprising parabolic-elliptical-heat-reflecting-infrarred-heat-source means constructed and arranged to produce movable lines of intense focussed heat at said bonding surface areas.

32. A method in accordance with claim 1 and further comprising monitoring the bonding zone continuously to establish substantial identity of temperatures at the surfaces to be joined, as well as rise thereof above a threshhold.

33. Method in accordance with claim 32 and further comprising modification of at least one of the heating and processing steps in response to the temperature monitoring.

34. Apparatus for practice of the method of claim 33 comprising rapidly translatable focussed IR heaters with directly associated IR monitoring means and constructed and arranged to be inserted and removed between confronting surfaces of opposed parts to be joined and while so inserted to be rapidly reciprocated, control means for heater temperature, insertion/removal and pressing conditions and thermal loop feedback means connected between said monitoring means and control means to enable an effective press joinder of the parts at their heated surfaces under pressure, time and temperature conditions suited to the particular parts.