arptech logo
about_us FAQ

Frequently Asked Questions related to Rapid Prototyping or Rapid Manufacturing technologies

Frequently Asked Questions

Frequently asked questions related to Rapid prototyping technologies. If you can't find your answer below, please feel free to contact us.

  • What is Rapid Prototyping?

    Rapid prototyping (RP) technology is used for building physical models and prototype parts straight from 3D CAD models, which is sectioned into many thin horizontal slices and data is passed to RP systems that join together liquid, powder and sheet materials to form complex parts layer by layer.

  • What is FDM?

    FDM also known as Fused Deposition Modeling is layered manufacturing process. FDM offers functional prototypes with ABS, and other materials. A thin bead of molten plastic is extruded through the computer controlled nozzle, which is deposited on a layer-by-layer basis to construct a prototype directly from 3D CAD data. The technology is commonly applied to form, fit and function analysis and concept visualisation. In addition, FDM can be used for pattern generation and rapid manufacturing.

  • What is 3d Printing?

    3d Printing is the less costly process of rapid prototyping which turns the 3D CAD data to quickly produce a three dimensional model for conceptual evaluation. Where an ordinary printer lays down a single 2D layer of ink on a sheet of paper, these printers add the extra dimension by printing layer after layer until you have a real, 3d object similar to your CAD model. Manufacturers report enormous productivity gains from using 3d printed parts.

  • What is SLA? and How SLA Process works?

    SLA also known as "Stereolithography", provides the greatest accuracy with an excellent surface finish. SLA parts are durable and these functional parts are suitable for wide variety of applications e.g. pre production, Product verification, Form/Fit/function testing, Snap fit assemblies, thin walled parts. Please check our SLA specification page for detailed information.

    How SLA Process works?

    Stereolithography process produces plastic parts directly from 3D CAD model; by solidifying the surface of a liquid photo polymer layer by layer with the help of a laser beam. When the laser beam hits the liquid, it solidifies the resin. When a layer is fully traced, the elevator is then lowered in the vat. The self-adhesive property of the material causes the layer to stick with each other and in this way a 3d part is formed in multi-layers.

  • What is SLS? and How SLS Process works?

    SLS also known as "Selective Laser Sintering", primarily used to quickly produce three -dimensional prototypes, parts, direct mold inserts, tools, and lost wax casting patterns. SLS process provides durable, metal, plastic or rubber like prototypes directly from CAD model. These prototypes can be used as test parts for form, fit and function. SLS technology provides broad range of materials e.g. rigid thermoplastics, stainless steel, polystyrene, thermoplastic elastomers, cast form plastic for investment castings. Please check our SLS specification page for detailed information.

    How SLS Process works?

    SLS process produces parts directly from 3D CAD model; layer by layer similar to SLA but rather than liquid resin powder is used. The CO2 Laser provides a concentrated heating beam which is traced over the tightly compacted layer of fine heat-fusible powder. The temperature in the entire chamber is maintained little below the melting point of the powder. So laser slightly raises the temperature to cause sintering, means welding without melting. For next level, piston moves down along with the formed object and powder is spread with a roller for next layer. Process repeats until full object is formed.

  • What are the main applications of Rapid Prototyping?

    Although there is a big listing of prototyping applications. This technology is maturing rapidly specially in automotive, medical, toys building, packaging, aerospace, electrical, scientific applications and so on.
    Few examples here:
    a) Imagine there is a major exhibition next week and your new product is still in development stage, How to get the part urgently? just send us your CAD file rest is up to us to meet your deadline.
    b) Why to take a risk of getting unrealistic quotes from your suppliers by sending 2d drawings, when you can send inexpensive 3d physical part which will not only help to save money at the end but also helps to open new options to manufacture the part or tooling.
    c) Manufacturers who need parts in small quantities where tooling or production cost is not justified.
    d) Sometimes it is difficult for the designers or toolmakers to visualize or find out the problems in the drawings, by having the 3d part in their hands, helps them to figure out the problem and redesign it if required before investing on actual tooling.
    e) Helps the medical field in many different ways specially for re-constructive surgery by making 3d models created from CT scan of the patient's body parts.
    f) Quickly making master model for vacuum casting to produce small quantity of Poly Urethane parts.
    g) If you are a student, scientist, teacher and you need to make a part for your next project or class demonstration, what to do? Rapid prototyping is the quick answer for you.
    h) Building my new home but like to see how the design will look like in real life.
    i) To make some Artistic or unique design for example statue, jewellery, special type of toy even some part is broken of your home appliance which is not easily available in the market.
    j) Any spare parts or auto parts hard to find in the market.
    k) Tooling inserts for plastic injection moulding direct in steel able to produce thousands of parts.
    l) For further applications and material details please feel free to contact us

  • What is STL format and how can I export from CAD package?

    STL file is simply a mesh of triangles wrapped around a CAD model was defined by 3D systems in 1980s. STL, name is derived from rapid prototyping process, StereoLithography, also known as abbreviation of Standard Triangulation Language. This very simple format has become an industry standard for the Rapid Prototyping sector. Virtually all modern CAD systems now include STL or Rapid Prototyping output as a standard feature.

    N.B. Sometimes we receive very low resolution STL files so now a days we recommend our clients to send us 3d cad files in one of these formats: IGES (IGS), STEP (STP), Parasolid (.x_t or .x_b)

    What to consider while creating STL file:

    Generating STL files is usually a fairly simple process. But every CAD system uses different terms and parameters for defining the STL file resolution. It's not necessary to understand all those parameters to produce useful STL file. Following is brief checklist which can help to produce good STL file:
    1) As a typical example mesh with triangles approximately the size between 0.02mm (.001") to 0.05 mm (.002") will produce a good quality STL file. Please keep in mind if you reduce mesh tolerance further down doesn't mean prototype accuracy will be improved. As a thumb rule parts with many contoured or curved surfaces need to have fine tolerance than straight geometric parts.
    2) STL files are always preferred to be saved in Binary format than Ascii mode.
    3) If you are using Solid CAD modeling package to create 3D model, there are less chances of having any error in STL file. For surface model please stitch/sew all surfaces together to make a single water tight model before exporting STL file. You may be still able to produce STL file from untrimmed or corrupt surfaces but will never get a clean STL file and its much harder to fix STL file than native CAD file.
    4) Generally STL file has no UNITS attached to it so its always good practice to send overall part sizes along with your STL file otherwise we wouldn't know your part dimensions. Most common units are MM or Inches.
    5) Some CAD systems will generate error messages during STL conversion showing that some part geometry is outside of the positive X, Y, Z quadrant or is in negative space. These warning messages can be ignored.
    6) Make sure to join all the solid model pieces to single entity which you want to see in a single prototype. Otherwise all those bits & pieces will end up separately in STL file and we'll have to spend time to join them together, unless you want them to be separately made.

    STL export guidelines from some of common CAD systems:

    1) File > Export > Rapid Prototyping
    2) Output type : Binary
    3) Triangle & Adjacency Tolerance: .05mm
    4) Set Auto normal Gen to ON
    5) Set Normal Display to OFF or ON
    6) Set Triangle Display to ON (good idea to leave ON so that you can see mesh pattern on your model)
    7) File Header Information: Press OK
    8) Sometimes it shows error messages "Negative coordinates found" which can be ignored
    1) File > Save a copy
    2) Add 'New Name' or copy and paste from 'Model name' and choose STL from type drop down menu. > Hit ok
    3) Accept 'binary' and 'negative value' defaults. Enter '0' in chord height box and system will set to minimum available.
    4) Set angle control to 1
    5) Check file name change if desired hit ok. File will be saved to your working directory.
    1) File > Export > Rapid Prototype File
    2) Select the part to be exported
    3) Select Prototype Device to SLA500.dat
    4) Set Absolute Facet Deviation to 0.01 mm/(0.000395")
    5) Select File type Binary and Save
    1) Open File > Save As
    2) Set file type as STL
    3) Select Options > Output as Binary
    4) Select the units mm or inches
    5) Select Quality > Fine
    6) Save
    1) Open Model & select File > Save As
    2) Select File type as STL
    3) Options > conversion tolerance to 0.0254 mm (0.001")
    4) Surface Plane Angle > 45°
    5) Select Binary type and OK
    6) Name & Save STL file
    1) Select STL command
    2) Maximum Seg to 0.0125mm
    3) Select the model and > select Yes
    4) Select Export > type File name > OK
    Note: STL can only be generated from 3D model not from 2D drawings or wireframe.
    1) Type "STLOUT" at the command prompt
    2) Select the objects to be exported
    3) Select "Y" for Binary format
    4) Type File name
    If you get error message "No Solids selected" try to move your model in positive octant.
    3D Studio Max
    1) Open Document and save as a new file.
    2) Select few items of your object at one time.
    3) Go to Modifiers => More => Select Mesh smooth => OK.
    4) Under parameters increase iterations by 2 or 3.
    5) If your part geometry is complex you may add more polygons.
    6) Now your wire frame model is defined with polygons.
    7) Once finished select all and export as an STL file.
    1) In the Graphics window Right click on the part
    2) Pick the Part Properties and Rendering
    3) Select Facet Surface smoothing to 160
    4) File and Export to an STL file
    1) File > Save As
    2) Select File Type to STL
    3) Select File Name > Save
    4) Select Binary
    5) Select Detail Controls from Mesh Options
    6) Max Angle = 20, Max aspect ration = 6, Min edge Length = 0.0001
    7) OK