In the past engineering was so weak in all aspects.During those yearss hospitalised people struggled alot.At the present twenty-four hours due to the promotion of engineering major surgeries on skull, articulatio genus, nose, jaw, limb etc became more easy.In the early 80 ‘s for making major implants on skull or knee traditional methods were used.Now improved engineering tends sawboness to near linear fabrication method for of import treatments.For skull implants physicians prefer Selective Laser Sintering method or inorder to construct the skull model.Then with the aid of this implants are made utilizing 3D printing ( Polyjet Printing Method ) .And the success rate of making surgery by this method is higher than ordinary methods.It is clear that the sum hazard factor is really less by linear fabrication implants.Like wise many Rapid prototyping methods are used in many serious surgeries.These implants are non merely used in skull, it can besides be used in surgeries with hip, articulatio genus articulations etc.
This study demonstrate about the usage of linear fabrication techniques in the medical field, and illustrates the importance of rapid prototyping on it.The overall position makes a clear vision of what all linear fabrication methods been used and how far it lifted up the medical watercourse.
TABLES AND CONTENTS
Medical field is considered as the most successful field. Due to the meliorate engineering bring arounding per centum of lesions, broken organic structure parts and so on reached the extremum.
Today the per centum of people who is acquiring injured or being hospitalised is at the upper limit. For all the instance infirmaries and intervention are compulsory. If we analyse the study it is clear that medical industry better quickly twenty-four hours by twenty-four hours around all corners of the universe. In add-on to it Technology helped medical sector widely which avoided complications, hazard etc.Many multispecialty infirmaries render perfect intervention in all kinds of job.
Many sawboness study the whole instance and with the aid of linear fabrication engineering, so they do the surgery.In many critical issues were resolved with R.P procedure. And this information will assist to supply a short study for the application of Additive Manufacturing in Medical side particularly in the surgical portion of human organic structure.
Basic Principles of Rapid Prototyping
Rapid prototyping ( R.P ) is defined as the combination of different methods by utilizing Computer Aided Design ( CAD ) information, to obtain a 3D object.
Rapid prototyping is besides known as Linear fabrication ( AM ) .The procedure makes the development more easy for bring forthing big graduated table and little graduated table products.Latest development in Computer Numeric Control ( CNC ) added it in the paradigm division [ 1 ]
Computer Numeric Control Machine ( CNC )
CNC machine is one of the oldest machine that is used in this modern epoch. Progressive betterment in the field define it as a paradigm. The higher stuff remotion and axes speed made CNC as a disputing one.The inclusion of Auto Cad and other planing package tends CNC a demanding machine. [ 2 ]
Advantages of CNC Machine [ 3 ]
CNC has many advantage over Additive Manufacturing methods. They are illustrated below: –
The cost of machine is really inexpensive comparison to R.P machines ( which comes under 10,000 $ ) .
CNC machines allow little mistakes.
Very big volume of merchandise can be obtained by CNC machines.
Accuracy rate is really high.
2 Rapid prototyping
Rapid prototyping is the procedure of doing paradigms with the aid of 3D CAD.It is a measure by measure process. The completed 3D Cad theoretical account is transferred into an appropriate package such as thaumaturgies from materialise where Rapid Prototyping machine can read the content. Then Standard Triangulation Language will look into the layout and fix if the 3D theoretical account is inappropriate. [ 4 ]
Furthermore with linear fabrication method the 3D merchandise is made. It is a bed by layer process. Each bed binds following and makes the merchandise more strong. Without the aid of expensive tools end product can be obtained. Very complex parts can be built easy with the aid of linear fabrication technique. Apart from that more than one merchandise can be made at a time.As a consequence, market of Additive Manufacturing machines became extremely on demand. [ 5 ]
1 Advantages of Rapid Prototyping
There are many advantages of Rapid prototyping over CNC. [ 6 ]
They are: –
Very Complex parts can be made easy
Crisp interior corner can non machined
Easy to utilize
Rapid Prototyping in medical surgery
Rapid prototyping method is used in many degree in the medical firm.Major surgeries in skull, leg, articulatio genus are done successfully utilizing A.M engineering. [ 7 ]
The R.P chiefly adds [ 8 ] : –
Implant design for the surgery
Industry of complex broken castanetss utilizing A.M
Complicated surgical planning are made easy
Linear Manufacturing Methods
Four linear manufactuirng techniques are explained in this study. They areSelective Laser Sintering ( SLS ) , 3D printing ( OBJET ) , Stereolithography ( SLA ) and Fused Deposition Modelling ( FDM ) . All the procedure are explained below.
Selective optical maser sinteringA ( SLS ) [ hypertext transfer protocol: //en.wikipedia.org/wiki/Selective_laser_sintering ]
Selective Laser Sintering is an linear fabrication technique that uses a high powerA laserA ( for illustration, aA C dioxide optical maser ) to blend little atoms ofA plastic, A metalA ( Direct Metal Laser Sintering ) , A ceramic, or glassA pulverizations into a mass that has a desired three-dimensional form. The optical maser selectively fuses powdered stuff by scanning cross-sections generated from a 3-D digital description of the portion ( for illustration from aA CAD file or scan informations ) on the surface of a pulverization bed. After each cross-section is scanned, the pulverization bed is lowered by one bed thickness, a new bed of stuff is applied on top, and the procedure is repeated until the portion is completed. This can be explained by a diagram below.
Untitled.png Schematic Diagram of SLS Figure 1
Compared to other methods of linear fabrication, SLS can bring forth parts from a comparatively broad scope of commercially available pulverization stuffs. These includeA polymersA such asA nylon, ( orderly, glass-filled or with other fillers ) orA polystyrene, metals includingA steel, A Ti, metal mixtures, and complexs andA green sand. The physical procedure can be fullA thaw, partial thaw, or liquid-phaseA sintering. And, depending on the stuff, up to 100 % denseness can be achieved with stuff belongingss comparable to those from conventional fabrication methods. In many instances big Numberss of parts can be packed within the pulverization bed, leting really high productiveness.
3.1.2 3D printing ( Polyjet ) [ http: //desktop3dprinter.com/polyjet-printer.php ]
Polyjet printing continues to use advanced and new attacks in 3D prototyping hardware, package and fiction stuffs. Polyjet printing and a map ofA rapid prototypingA engineering is a design procedure utilizing computing machine programming to steer the creative activity of a three dimensional theoretical account through the layering of fiction stuff. The Polyjet caputs sedimentation fiction stuff in a edifice tray bed by bed and with concise preciseness until the paradigm is built to finish specifications. Polyjet pressmans are able to utilize many different types of fiction stuffs to construct theoretical accounts and paradigms. Polyjet engineering uses rosins, polymers or photopolymers either singularly or in different combinations to construct many different types of models.Working method can be explained with the aid of a diagram: – pol2.png
Conventional Diagram of Polyjet Printer Figure 2
Polyjet printing caputs are able to layer precise sums of fiction stuff during the layering procedure and construct paradigms quickly and consequently to plan specifications. During assorted phases of the Polyjet edifice procedure ultra-violet visible radiations cure the fiction stuffs which harden and produce a functional theoretical account or paradigm. The Polyjet printing procedure is simple and easy including apparatus, printing and cleansing of the paradigm theoretical account or merchandise.
Stereolithography ( SL ) [ hypertext transfer protocol: //en.wikipedia.org/wiki/Stereolithography ]
Stereolithography is an linear fabrication procedure utilizing a VAT of liquid UV-curableA photopolymerA ” rosin ” and aA UVA laserA to construct parts a bed at a clip. On each bed, the optical maser beam traces a portion cross-section form on the surface of the liquid rosin. Exposure to theA UVA laserA lightA remedies, or, solidifies the form traced on the rosin and adheres it to the bed below.
After a form has been traced, the SLA ‘s lift platform descends by a individual bed thickness, typically 0.05A millimeters to 0.15A millimeter ( 0.002 ” to 0.006 ” ) . Then, a resin-filled blade expanses across the portion cross subdivision, re-coating it with fresh stuff. On this new liquid surface, the subsequent bed form is traced, adhering to the old bed. A complete3-DA portion is formed by this procedure. After edifice, parts are cleaned of extra rosin by submergence in a chemical bath and thenA curedA in aA UVA oven.
Conventional Diagram of SLA figure 3
Stereolithography requires the usage of support constructions to attach the portion to the lift platform and to forestall certain geometry from non merely debaring due to gravitation, but to besides accurately keep the 2-D cross subdivisions in topographic point such that they resist sidelong force per unit area from the re-coater blade. Supports are generated automatically during the readying of 3-DA CADA theoretical accounts for usage on the stereolithography machine, although they may be manipulated manually. Supports must be removed from the finished merchandise manually ; this is non true for allA rapid prototypingA engineerings.
Fused Deposition Modelling ( FDM ) [ hypertext transfer protocol: //express.redeyeondemand.com/FDM.aspx ]
Fused Deposition ModelingA Process uses run plastics or wax extruded by a nose that traces the parts cross sectional geometry bed by bed. FDM creates tough parts that are ideal for functional usage.It can be shown by a figure.
fdm_process.jpgSchematic Diagram of FDM figure 4
An FDM machine consists of the undermentioned parts a physique platform, filament provender devices, heated bulge noses and a nozzle control setup. The whole system is contained within a het environment to cut down the sum of energy needed to run the fibril at the nose. The FDM procedure feeds fibrils of build stuff and support stuff to heated noses. These noses are used to put down liquefied fibrils of physique and support stuffs in the coveted cross sectional geometries. Once the first cross subdivision is completed the physique platform is lowered one bed thickness and the following cross subdivision is printed. This procedure is continued until the portion is completed. Once complete, the portion can be taken out and any support constructions can be removed.
The chief advantage to utilizing FDM is the really lasting parts that can be made utilizing waxes and assorted technology plastics. The drawback to utilizing the FDM method is that the parts by and large take much longer to construct and the layering is clearly seeable because of the bulge type procedure.
Applications of Additive Manufacturing Techniques
Selective optical maser sinteringA ( SLS )
“ Selective optical maser sintering engineering was introduced by The University of Texas and out in the twelvemonth 1987 ” .And during the twelvemonth 1992, the 1st SLS system exported and now many systems are used worldwide.
Today many medical sector prefer SLS fabrication engineering inorder to do outlayer of skull. This aid the sawboness to acquire the clear cut informations about the jobs. While repairing implants physicians are really cautious about the devising of implants.Since the skull is non been wholly symmetrical, the broken portion is uneasy to repair the orginal skull faultlessly.
SLS theoretical account of skull with implant figure5
For that purpose a skull theoretical account is designed through CAD package and made utilizing
SLS technology.In the past stereolithography method was used during such surgeries. “ Now SLS is widely used since the engineering produces stiff and resistable polymeric amide parts, because the stuff is comparatively inexpensive, and ingestion is much low. “ In here polymeric amide is the common plastic constituent used. Furthermore, metallic and ceramic pulverizations are more used in the process.These pulverization is stored in little armored combat vehicle near the work area.Then utilizing roller it is extended on to the bed.
3D printing ( Polyjet )
3D is the procedure by which “ liquid binder is jetted ” on a powdery platform, so that needed portion can be obtained.3D printing procedure is more faster than other rapid prototyping techniques. ( )
3D polyjet Implant figure 6
In medical side physicians prefer 3D printing ( polyjet ) for skull nidation. With the aid of this engineering, implants are made by “ photopolymeric rosin ” . Prominent item about portion avoids support. And the semitransparent coloring material esthesis makes the portion more seeable. It helps physicians for making the surgery absolutely. The method is really fast and it avoids annoyance, emotional emphasis and so on. This will let go of the hazard factor in a immense footing. “ 3D pressmans are widely used in medical modeling due to their punctilious truth, rapid build clip and easiness of theoretical account sterilization. Models are besides extremely reslient, enabling boring and repairing with similar features to human bone tissue. Furthermore, saving of thin and delicate constructions due to miss of an after-production measure make it possible to construct complex theoretical accounts of human anatomical constructions such as blood vass ” .
Stereolithography ( SL )
During the twelvemonth 1987 the 1st rapid prototyping procedure was introduced. Stereolithography has improved due to the new execution of design. Now a yearss this method is used in many medical surgical processs. This method is used for complex medical interventions. In the articulatio genus surgery that is the Medial Tibial Plateau, stereolithography method is used for repairing the implant.
Using CAD package the solid theoretical account of it is changed to STL file. The STL file is read and SLA scan the outlayer of the theoretical account. Laser cuses the liquid rosin and forms the desirable form. For this procedure polymeric amide rosin is used. The manufactured out layer gives a elaborate vision to the physician. Before making the surgery the sawboness analyse, and the geometric construction give a three dimensional position of anatomical information to guarantee whether there is sufficient bone for support after cutting the portion of organic structure. The undermentioned diagram shows the broken bone of a median tibial tableland.
Medial Tibial Plateau Model figure 7
Stereolithography is widely used for many major surgeries. It is used in craniofacial, tumour, rehabilitative surgeries. The new technique utilizing colored stereolithography is used in 3D theoretical accounts. ” The 3D information of a solid theoretical account combined with the excess information from the selective coloring of certain anatomical constructions both combine as an ultimate diagnostic and preoperative
be aftering tool ” . During the clip of tumour surgeries the coloring of the theoretical account helps to rectify connexion composing “ paranasal fistulas, the
orbit, the infratemporal pit ”
Fused Deposition Modelling ( FDM )
Fused Deposition Modelling is a procedure by which stuff is squeezed out with high force per unit area, bed by bed for bring forthing the 3D component. It was invented in the twelvemonth 1988.And from 1992 onwards, FDM started used widely in many sectors. In the medical field this procedure is used for the industry of Limb. The out bed of the theoretical account is designed, and through STL file it is transmitted into the machine. It can be illustrated with the aid of a diagram.
Build3.gif Build.gif FDM Stages for the industry of Limb figure 8
During the procedure with high temperature and force per unit area ABS stuff is extruded out from the nose. It make layer by bed layout and solidify to organize the unreal Limb.It can be shown with the aid of a diagram.
Final Layout of Artificial Limb figure 9
After the fiction the merchandise is send for external lamination to do the limb more attractive.Due to its flawlessness, many sawboness prefer this method for such instances. The most advantage of this technique is stableness of the stuffs. Prototypes obtained is used for fit testing. The limb manufactured utilizing this method will avoid emphasis, at the same clip similar procedure is used for doing articulatio genus screen which is another application portion of FDM.
Merits and De Merits of Rapid Prototyping Techniques
Selective optical maser sintering ( SLS )
Different sorts of stuffs are used
Support can be easy removed since pulverization plays the back uping function
It is speedy and inexpensive for doing complicated theoretical accounts
Partss can interrupt easy
Problems with dust
Accuracy is less
Very fast procedure
Less expensive merchandises can be obtained
Materials with amylum can be casted easy
Different coloring material theoretical accounts can be obtaine
Lack of surface coating
Stereolithography ( SLA )
Accuracy is high
It has 10plus old ages of projecting experience
Very perfect end product
Very little objects can be made easy
Merely really few assortments of stuffs can be used
It is really difficult to do thin parts
The cost is excessively high ( photopolymer )
Fused deposition modeling ( FDM )
Procedure is unsophisticated
Machine can run in office ambiance
End product can be obtained with different stuffs
It takes much clip for the full procedure
Materials used for support are wasted
It is a must to take the support stuff
Requirements of Cad in Rapid Prototyping
CAD play a critical function in planing a theoretical account for farther development. Over 20years CAD package were used in many industrial administration. Since the demand of design gets turning, industries prefer bounder for their scheming side. CAD demand is a must in rapid Prototyping. Meanwhile CAD internally uses a file called Standard Triangulation Language ( STL ) . In between the CAD and Rapid Prototyping, STL acts as a medium for bring forthing CAD design into a format for Rapid Prototyping machines. This format is adopted by Rapid Prototyping and Rapid Tooling. The feature of STL file depends on the quality of NURB. Whereas the STL toolkits available inside the file reconstruct the corrupted STL and better their characteristic.
Rapid Prototyping for Specification and Suitability
Linear fabrication techniques rendered positive impacts to the medical engineering. Depending upon the type of implants, outlayer and theoretical accounts, different rapid prototyping methods are used. The following tabular array explains the choice procedure for continuing surgeries.
Specification and Suitability
Sodium lauryl sulphate
Need of Support
Meritorious theoretical account