Background technology
Melt extruded formula three-dimensional printer is called melt extruded formula fast forming machine again, the shower nozzle of this printer is heated to be molten state with plastics silk material, the workpiece figure control instruction of sending according to computer then, melting charge is extruded and optionally be deposited on by the small nozzle in the shower nozzle on the workbench substrate of below, constitute the ground floor X-Y scheme cross section of workpiece.After this layer shaping finished, the shower nozzle little layer height that rises carried out the shaping in second layer X-Y scheme cross section according to the similar procedure of ground floor, this stacked being added on the last layer, and be bonded to each other and be one.Repeat two dimension so from level to level and be shaped, be shaped up to whole 3 D workpiece and finish.
Above-mentioned forming technology belongs to the addition autofrettage, need not traditional machining lathe and tool and mould, under the control of computer, but the three-dimensional CAD model direct forming 3D solid according to workpiece, thereby be called free forming, and be fit to very much the development of new product, can save man-hour and cost greatly.
Traditional melt extruded formula three-dimensional printer has following two characteristics at present: (1) adopts the roller pair by frictional force plastics silk material to be sent to the shower nozzle heating and melting and it is extruded from nozzle; (2) adopt two shower nozzles, the moulding material of one of them shower nozzle melt extruded deposition workpiece constitutes workpiece; Another shower nozzle extruding deposition backing material also constitutes supporting construction, in order to avoid workpiece caves in forming process and buckling deformation.The shortcoming that causes thus is: (1) roller and the frictional force of silk between the material are limited, therefore extrude power and extrude flow limited, are difficult to realize the efficient shaping of high density workpiece; (2) at each layer that is shaped, two shower nozzles must take turns to operate and frequent location, and the forming technology complexity significantly reduces forming efficiency; (3) every forming machine must have two shower nozzles, two charging trays and two mantle fiber material feed mechanisms, makes frame for movement and control system more complicated.
Fig. 1 shows the structural representation of traditional melt extruded formula three-dimensional printer.See also Fig. 1, traditional melt extruded formula three-dimensional printer overlaps shower nozzles and feed mechanism and workbench by two to be formed, and specifically comprises: charging tray 1 ' and 12 ', plastics silk material 9 ' and 13 ', motor 8 ' and 14 ', roller pair 7 ' and 15 ', shower nozzle 6 ' and 11 ', nozzle 5 ' and 10 ', workbench 2 ' andsubstrate 3 '.During work, instruction according to computer control system (not shown), the shower nozzle 6 ' on Fig. 1 right side at first moves to the appropriate location of workbench 2 ' top, motor 8 ' drives the roller pair 7 ' that is made of a pair roller, by roller pair 7 ' and the clamping frictional force of silk material 9 ' wherein, drive enters shower nozzle 6 ' from the silk material 9 ' of charging tray 1 ', under the effect of electrically heated rod in shower nozzle 6 ' (not shown), a silk material 9 ' that enters shower nozzle 6 ' is heated and is molten state, and under the promotion of follow-up silk material 9 ', extrude from small nozzle 5 ', be deposited on the substrate 3 ', progressively solidify to form the supporting construction of workpiece 4 ' one layer cross section.
Then, the one cover shower nozzle in Fig. 1 left side moves to the appropriate location of workbench 2 ' top, motor 14 ' driving rolls pair 15 ', by roller pair 15 ' and the clamping frictional force of silk material 13 ' wherein, drive enters shower nozzle 11 ' from the silk material 13 ' of charging tray 12 ', under the effect of electrically heated rod in shower nozzle 11 ' (not shown), a silk material 13 ' that enters shower nozzle 11 ' is heated and is molten state, and under the promotion of follow-up silk material 13 ', extrude from small nozzle 10 ', be deposited on the substrate 3 ', progressively solidify to form the structure of workpiece 4 ' one layer cross section.
Obviously, during above-mentioned traditional melt extruded formula three-dimensional printer Forming Workpiece, two shower nozzles must take turns to operate and frequent location, the forming technology complexity, significantly reduce forming efficiency, and the frictional force between roller and the silk material is limited, extrudes power and extrudes limited and difficult the stablizing of flow, is difficult to realize the efficient shaping of high density workpiece.
Summary of the invention
The objective of the invention is to address the above problem, a kind of single shower nozzle melt extruded formula three-dimensional printer is provided, forming efficiency height, workpiece are closely knit, the more compact structure of forming machine.
Technical scheme of the present invention is: the present invention has disclosed a kind of single shower nozzle melt extruded formula three-dimensional printer, comprises shower nozzle, feeding device, rotary drive system, moved cross beam, workbench, fuselage, computer control and drive system, wherein:
Described shower nozzle is used for heating and an extrusion molding silk material, comprises screw rod;
Described feeding device is used for storing and sending a material to, comprises the roller pair;
Described rotary drive system is used for driving described screw rod and described roller pair;
Described moved cross beam links to each other with described fuselage, be used for the described shower nozzle of carrying and described rotary drive system, make the described relatively moved cross beam of shower nozzle do the left and right horizontal motion, described relatively fuselage moves up and down again, in order to regulate described shower nozzle with respect to the distance of described workbench, and behind a layer cross section of Forming Workpiece, drive floor height of this shower nozzle rising, reshape next layer cross section of workpiece;
Described workbench is positioned at the below of described shower nozzle, links to each other with described fuselage, be used for the carrying Forming Workpiece, and described relatively fuselage is done the horizontal movement of front and back;
Described fuselage carries whole three-dimensional printer;
Described computer control and drive system are used for automatic control and the driving of complete machine;
Described three-dimensional printer makes single shower nozzle be formed separately workpiece and supporting construction by the free forming process optimization, and workpiece was easy to separate with supporting construction after shaping was finished.
According to an embodiment of single shower nozzle melt extruded formula three-dimensional printer of the present invention, described rotary drive system comprises stepper motor, the pinion unit freewheel clutch of unifying, wherein:
Described rotary drive system drives described material extrusion screw rod and described feed roller wheel set with described gear train assembly;
Described freewheel clutch prevents the counter-rotating of described stepper motor and causes a material to withdraw from from described shower nozzle.
According to an embodiment of single shower nozzle melt extruded formula three-dimensional printer of the present invention, described shower nozzle also comprises barrel, nozzle, electrically heated rod and thermocouple, wherein:
The upper end of described screw rod links to each other with the output shaft of described stepper motor, is used for extruding a material;
Described barrel is positioned at the outside of described screw rod, is used for storing the silk material of fusion;
Described nozzle links to each other with the lower end of described barrel, as the extrusion of silk material;
Described electrically heated rod has two, lays respectively in described barrel and the nozzle, is respectively applied to heat silk material and nozzle in the described barrel;
Described thermocouple has two, lays respectively in described barrel and the nozzle, is respectively applied to control the heating-up temperature of barrel and nozzle.
Embodiment according to single shower nozzle melt extruded formula three-dimensional printer of the present invention, described feeding device also comprises charging tray, charging aperture, wherein said charging tray places the right side of described shower nozzle, be used for twining the silk material, described roller sub-folder is held from the silk material of described charging tray extraction and is forced it to enter described shower nozzle, described charging aperture links to each other with the top of described barrel, as the entrance of silk material.
According to an embodiment of single shower nozzle melt extruded formula three-dimensional printer of the present invention, described moved cross beam also comprises servomotor, ball-screw and line slideway, wherein:
Described servomotor changes the deposition position of extruding a material according to the motion of workpiece cross section graphics driver shower nozzle left and right horizontal;
Described ball-screw is transformed to rectilinear motion with rotatablely moving of described servomotor;
Described line slideway is used for the guiding of described shower nozzle left and right horizontal motion.
According to an embodiment of single shower nozzle melt extruded formula three-dimensional printer of the present invention, described workbench comprises servomotor, ball-screw and line slideway, wherein:
Described servomotor changes the deposition position of extruding a material according to horizontal movement before and after the graphics driver workbench of workpiece cross section;
Described ball-screw is transformed to rectilinear motion with rotatablely moving of described servomotor;
Described line slideway is used for the guiding of described workbench front and back horizontal movement.
The present invention contrasts prior art following beneficial effect: technical scheme of the present invention is to adopt roller pair and screw rod to send and extrude a material to, by extruding precision control and the process optimization of a material, only needs single shower nozzle just can be formed separately workpiece and supporting construction.With respect to traditional three-dimensional printer, have that material extrusion power is big, discharging is stable, only need single shower nozzle just can be formed separately that workpiece and supporting construction, forming efficiency height, workpiece are closely knit, the advantages such as more compact structure of forming machine.
The specific embodiment
The invention will be further described below in conjunction with drawings and Examples.
Fig. 2 shows the structure chart of the embodiment of a kind of single shower nozzle melt extruded formula three-dimensional printer of the present invention.See also Fig. 2, single shower nozzle melt extruded formula three-dimensional printer mainly comprises following part: shower nozzle, feeding device, rotary drive system, moved cross beam, workbench, fuselage, computer control and drive system.
Shower nozzle 2 heating and extrusion molding comprisescrew rod 3,barrel 20,nozzle 22, electrically heatedrod 19 and 21 with the silk material, andthermocouple 1 and 25.
Feeding device stores and sends a material to, comprises roller pair (roller 16,17), chargingtray 15,charging aperture 18.
Rotary drive system comprisesstepper motor 7, gear train assembly (gear 6,8,9,5,10,11,13,12) and freewheel clutch (shown in Figure 3 26).
Workbench comprises servomotor, ball-screw and line slideway.
Shower nozzle 2 heating and an extrusion molding silk material 14.The upper end ofscrew rod 3 links to each other with the output shaft ofstepper motor 7, is used for extruding a material 14.Barrel 20 is positioned at the outside ofscrew rod 3, is used for storing thesilk material 14 offusion.Nozzle 22 links to each other with the lower end ofbarrel 20, as the extrusion of silk material.Electrically heatedrod 19 is arranged inbarrel 20, is used for the silk material of heating cylinder 20.Electrically heatedrod 21 is arranged innozzle 22, is used for heatednozzle 22, makes silk material wherein keep molten state.
Feeding device stores and sends a material to, and wherein chargingtray 15 places the right side of shower nozzle 2, is used for twining the silk material.The roller sub-folder is held from the silk material of chargingtray 15 extractions and is forced it to enter shower nozzle 2, and chargingaperture 18 links to each other with the top ofbarrel 20, as the entrance of silk material.
Roller pair in rotary drivesystem drive screw 3 and the feeding device is to comedrive screw 3 and roller pair with gear train assembly in the present embodiment, and freewheel clutch 26 preventsstepper motor 7 counter-rotatings and causes a material to withdraw from from shower nozzle 2.
Moved cross beam links to each other with fuselage, carrying shower nozzle 2 and rotary drive system, make the described relatively moved cross beam of shower nozzle do the left and right horizontal motion, fuselage moves up and down relatively again, in order to regulate shower nozzle 2 with respect to the distance of workbench, and behind a layer cross section of Forming Workpiece, drive floor height of shower nozzle 2 risings, reshape next layer cross section of workpiece.
Workbench is positioned at the below of shower nozzle 2, links to each other with fuselage, is used for the carrying Forming Workpiece, and the horizontal movement before and after fuselage is done relatively.Fuselage then carries whole three-dimensional printer.Servomotor changes the deposition position of extruding a material according to the 2 front and back horizontal movements of workpiece cross section graphics driver shower nozzle.Ball-screw is transformed to rectilinear motion with rotatablely moving of servomotor.Line slideway is used for the guiding of workbench front and back horizontal movement.
Particularly, the three-dimensional printer of present embodiment can be made up of shower nozzle 2,screw rod 3,barrel 20,nozzle 22, electrically heatedrod 19 and 21,thermocouple 1 and 25,stepper motor 7,gear 6,gear 8, gear 9,gear 5,gear 10,gear 11,gear 13,gear 12,roller 16,roller 17,charging tray 15,charging aperture 18,silk material 14,workbench 24 and substrate 23.According to the instruction of computer control and drive system (not shown),stepper motor 7 starts, drivenwheel 6 and with itsmeshed gears 8, then by with the coaxial gear 9 ofgear 8 and with itsmeshed gears 5, drivescrew rod 3 rotations.Gear 9 again freewheel clutch 26 (Fig. 3) drivenwheel 10 by wherein and with itsmeshed gears 11 andgear 13,gear 13 by with another gear (not shown) drivenwheel 12 of its engagement, therefore with the coaxialactive roller 17 ofgear 13 andactive roller 16 rotations coaxial with gear 12.Because another return idler (not shown) is arranged at the rear ofroller 17, these two rollers are formed the roller pair; Also there is another return idler (not shown) at the rear ofroller 16, and these two rollers are also formed the roller pair.Thetight silk material 14 wherein of above-mentioned two pair roller sub-folders, so whenactive roller 17 andactive roller 16 rotations, by the frictional force of these two roller surface withsilk material 14, can pull outplastics silk material 14 from chargingtray 15, and make amaterial 14 enter shower nozzle 2 throughcharging apertures 18, in shower nozzle 2 under the effect of electrically heatedrod 19, the silk material is molten state and under the extruding ofscrew rod 3, from the aperture ofnozzle 22, extrude, be deposited on thesubstrate 23, progressively constitute the cross section of workpiece.
Fig. 3 shows a kind of freewheel clutch 26 that the present invention adopts, and is made up of star-wheel 27, outer ring 28, roller 29 and spring spindle 30.Outer ring 28 closely links to each other with the endoporus of gear 9, and the endoporus 31 of star-wheel 27 closely links to each other with gear 10.When the outer ring 28 of freewheel clutch 26 under the driving of gear 9, during along counter rotation, roller 29 is subjected to the left side narrower region of the groove of effect wedging between star-wheel 27 and outer ring 28 of frictional force, freewheel clutch 26 is in engagement state, thereby drive star-wheel 27 and thegear 10 that links to each other with its endoporus 31 rotates, so by withgear 10 meshedgears 11, andgear 13 andgear 12,roller 17 androller 16 order about amaterial 14 and enter shower nozzle 2.When the outer ring 28 of freewheel clutch 26 under the driving of gear 9, when being rotated in a clockwise direction, roller 29 is subjected to the effect of frictional force, overcome the thrust of spring spindle 30, move to the wider part position, groove right side between star-wheel 27 and the outer ring 28, no longer wedging is in groove, and freewheel clutch 26 is in released state, thereby can not drive star-wheel 27 andgear 10 rotations, amaterial 14 is withdrawed from by shower nozzle 2.
The present invention adopts the purpose of freewheel clutch 26 to be in the feed mechanism ofsilk material 14, whenstepper motor 7 is rotated along normal direction by the requirement that is shaped, can drivesilk material 14 and enter shower nozzle 2; Andstepper motor 7 can not make amaterial 14 be withdrawed from by shower nozzle 2 during along opposite spin.
When adopting each cross section of melt extruded formula three-dimensional printer Forming Workpiece, at each terminal point of cross section figure,stepper motor 7 must stop operating immediately, makes shower nozzle 2 stop to extrude amaterial 14 immediately.But even so, because the inertia ofscrew rod 3 and other rotating parts, and the overbottom pressure effect offusion silk material 14 in the shower nozzle 2, a spot ofmaterial 14 still can leak fromnozzle 22, causes " hydrostomia " phenomenon, the surface quality of heavy damage Forming Workpiece.Adopt after the freewheel clutch 26, when shower nozzle 2 moves to the relevant position of workpiece cross section figure terminal point, the a bit of time of counter-rotating just stops then fast to makestepper motor 7, will in thenozzle 22 of shower nozzle 2, produce parital vacuum like this, asilk material 14 can't be leaked, guarantee the surface quality of Forming Workpiece.In the process thatstepper motor 7 reverses fast, because the effect of freewheel clutch 26 can not make amaterial 14 be withdrawed from by shower nozzle 2, thereby can not make an appearance silk material deficiency in the shower nozzle 2, the stability that amaterial 14 is sent to and extruded can be do not influenced, the accuracy of material deposition can be improved greatly.
Single shower nozzle melt extruded formula three-dimensional printer embodiment of the present invention can be formed separately workpiece and supporting construction.Requirement for supporting construction is: in (1) forming process, supporting construction should be able to support the workpiece bracketed part that is being shaped effectively, it can not be caved in and buckling deformation, so supporting construction should have enough intensity and rigidity.(2) after shaping was finished, supporting construction should be able to easily be separated with workpiece, can not produce tangible scar at surface of the work, so supporting construction can not have too high intensity and rigidity again.For overcoming these two contradictions that require existence, the present invention has adopted the measure of following free forming process optimization.
One of free forming process optimization measure: staggered floor is shaped, in order to reduce the interfacial bonding strength between supporting construction and the workpiece, being beneficial to is shaped finish after the separating of workpiece and supporting construction.
Fig. 4 a-4b shows the staggered floor shaping schematic diagram of the embodiment of the invention.Shown in traditional Fig. 4 a, when workpiece 100 has cantilever 200, for supporting extension arms 200 when being shaped, must be between cantilever 400 to 200, in the time of every shaping one deck workpiece cross-sectional layers, shaping one deck supporting construction 300, the shaping floor height h that the height of this part supporting construction equals 3 times.Adopt the shortcoming of above-mentioned forming technology to be, in the land 200 and 400 of workpiece and supporting construction, the bond strength of workpiece and support is similar to the interfacial bonding strength of workpiece, because this high-intensity combination, supporting construction was difficult to separate with workpiece after shaping was finished.For overcoming this drawback, the present invention proposes staggered floor shaping (shown in Fig. 4 b), namely be shaped in the following order: press floor height h, Forming Workpiece layer 500-presses floor height h, Forming Workpiece layer 600-shower nozzle rising 0.5h, shaping supporting layer 700-shower nozzle rising 0.5h, Forming Workpiece layer 800-shower nozzle rising 0.5h, shaping supporting layer 900-shower nozzle rising 0.5h, Forming Workpiece layer 1000-shower nozzle rising 0.5h, shaping supporting layer 1100-shower nozzle rising 0.5h, Forming Workpiece layer 1200-shower nozzle rising 0.5h, shaping supporting layer 1300.The result who is shaped by above-mentioned staggered floor is, the floor height of supporting layer 700 left parts is 1.5h, the flow of extruding a material owing to screw rod 3 among Fig. 2 remains unchanged, therefore compare during for h with the shaping floor height, the silk material density of supporting layer 700 left parts deposition is lower, and the bond strength of the land 400 of workpiece and support is also lower.In like manner, the floor height of workpiece layer 1200 right parts is 1.5h, and the silk material density of deposition is lower, and the bond strength of the land 200 of workpiece and support is also lower.Because the staggered floor forming technology has reduced the bond strength of land 400 and 200, so be easy to separate supporting construction from drip molding after shaping is finished.
Two of free forming process optimization measure: the support offset is set, in order to reduce the bond strength of supporting construction and side surface of workpiece.
Fig. 5 a-5b shows the support offset schematic diagram of the embodiment of the invention.Shown in traditional Fig. 5 a, be shaped according to thetheoretical path 51 in workpiece cross section and thetheoretical path 54 of supporting construction, and whennozzle 53 moves to the left end point of supporting construction forming path, because the silk material of extruding has certain width W, have the part supporting construction andworkpiece profile 52 crosses, cause supporting construction to be combined with workpiece closely, be shaped and finish that the latter two are not easily separated.For overcoming this drawback, the present invention proposes the concept (shown in Fig. 5 b) that supports offset, when generating forming path, with theworkpiece profile 52 certain distance C (shown in dotted line among Fig. 5 b) of setovering laterally, this distance C is called the support offset.Supporting offset can not be too big, otherwise does not have the effect of support; Can not be too little, otherwise support is not easily separated with workpiece, supports offset C=0.5W usually.In order to reach better effect, can determine the value of C by engineer testing.When the value of C was suitable, supporting construction should have a small amount of the contact with workpiece profile, and separated easily.
Three of free forming process optimization measure: adopt different cross section filling modes, in order to improve the intensity of workpiece, suitably reduce the intensity of supporting construction.
Fig. 6 a-6c shows the workpiece cross section filling mode schematic diagram of the embodiment of the invention.In order to improve the surface quality of workpiece, adopt the circular scanning filling mode in cross-sectional layers nearworkpiece neighboring area 61; Theinterior zone 62 of workpiece adopts 45 dip-parallel line sweep filling mode (shown in Fig. 6 a).And adopt opposite 45 dip-parallel line sweep filling modes (shown in Fig. 6 b) at theinterior zone 63 with the cross-sectional layers workpiece of postforming, so, the interstitial wire of the interior zone of adjacent two layers workpiece mutually vertical (shown in Fig. 6 c), the intensity of workpiece interior zone is strengthened.
And supporting section adopts constant parallel line sweeping filling mode (as shown in Figure 7), scanning direction unanimity between adjacent layer, the scanning filling distance between centers of tracks is bigger, for example, when nozzle inside diameter is 0.5mm, supports the scanning filling distance between centers of tracks and can be taken as 1mm, the supporting construction of Cheng Xinging is more loose like this, intensity is not high, is easy to separate with workpiece after shaping is finished.
Four of free forming process optimization measure: adopt different material extrusion speed Forming Workpiece and supporting construction, guaranteeing to support and to be shaped smoothly and to have on certain intensity based, the material extrusion speed that suitably reducing is shaped supports (for example be Forming Workpiece material extrusion speed 80%), make supporting construction more loose, be easy to separate with workpiece after shaping is finished.
After adopting the invention described above frame for movement shown in Figure 2 and process optimization measure, only need a single shower nozzle just can be formed separately workpiece and supporting construction, shaping finishes that the latter two are easily separated, and drip molding is closely knit, forming efficiency height, the more compact structure of machine.
Above-described embodiment provides to those of ordinary skills and realizes or use of the present invention; those of ordinary skills can be under the situation that does not break away from inventive concept; above-described embodiment is made various modifications or variation; thereby protection scope of the present invention do not limit by above-described embodiment, and should be the maximum magnitude that meets the inventive features that claims mention.