Please enable JS

Aerospace | Architecture | Art | Automobile | Biopharma | Bottling | Construction | Consumer Products | Educational Aids | Electronics | Energy | Fashion | Furniture | Gifting | Healthcare | Interior | Jewelry | Medical and Dental | Packaging | Robotics


Precision manufacturing of every industry

Polyjet | FDM | FFF | SLS | SLA | Micro SLA | CNC


We3dX allows you to track your product status with us. From order raised to shipment dispatched. For clients, who have raised a design order and industrial order with us; see how you can track from file upload to final product!

Watch this space for a product reveal soon!!! Did you visit Nozzberry yet? Don't miss on curated content, never!


Injection Moulding

Injection moulding is used when high volume of manufacturing production is needed. As it offers high repeatability and design flexibility which makes it a reliable choice. It dramatically low the cost of per unit but has a high setup cost.

Pros and Cons

Pros

  • Most cost efficient for high volume production of identical parts.
  • Material choice for injection moulding is vast. Properties of which can changed according to our specific requirements.
  • High productivity and repeatability.

Cons

  • Only suitable for large scale production with minimum 1000 parts, due to its high start-up cost.
  • Improvement during designing process is costly as design is modified in the mould.
  • Slow turn-around time which depends upon part complexity and size of production.

Injection Moulding Common Defects

  • Warping: Material bending due to uneven deformation and cooling. Using consistent wall thickness, which are not very thick or thin and avoiding sharp edges will prevent warping.
  • Sinking: Contraction of centre of the face due to uneven cooling. Hollowing out dense sections and thinning the wall thickness prevents sinking.
  • Weld lines: Discolouring deformation when two different flows meet but not fully blend, forming weld lines. By using material of lower viscosity and limiting the size of the parts and holes in it prevents weld lines.
  • Underfills and burn marks: Air might get trapped during injection which causes it to be under fill. The trapped air temperature might rise and can cause burn marks. To avoid this make an vent hole at critical position.

Fabrication process of Injection Moulding

  • Dried polymer granules are placed in the hopper where they go through reinforcing activities and colour pigment is added.
  • Granules are put into the barrel where they are heated and mixed. They are sent towards the mould by variable pitch screw whose geometry is optimized along with barrel such that it builds up pressure to the correct level for melting material.
  • The melted plastic is taken forward by moving ram and is injected into the mould through runner system. The whole cavity is filled and as material cools down, it turns solid and take shape of the mould.
  • Ejector pins push out solid part when mould opens. The mould then closes and goes through the same process.


CNC Process

CNC Working

 

CNC Milling

 

Most commonly used machine system in CNC is milling. A rotational cutting tool is used to remove material.

Working

 

  1. Using technical drawings of CAD model as base G-code is generated which is a series of commands followed by CNC machine.

  2. A blank work piece material is placed on the platform directly or using vice after cutting it to its size. Special measurement tools are used for accurate alignment and positioning.

  3. A rotational cutting tool rotating at high RPM removes material from block to create the designed part under several phases. At initial the material is removed quickly under approximate geometry then later more accurate finishing phases are used to produce final part.

  4. A setup can be changed to get the details which cutting tool was not able to get in initial setup. 5-axis CNC system eliminates the multiple setup problem faced by 3-axis system.

  5. To smoothen the rough edges due to deformation of material, they are to be deburred manually.



CNC Turning

CNC turning produces faster and more cost efficient product than milling parts. A stationary cutting tool removes material from part mounted on rotating chuck. For cylindrical profile, lathe machines are used and for non-cylindrical multi-axis CNC turning centres with milling tool attached.

Working

  1. From CAD model G-code is generated and then a blank cylindrical material of suitable diameter is loaded into the chuck.

  2. The chuck starts rotating at high speed and a stationary tool progressively removes material until the desired geometry is created.

  3. To create hole along centre axis, a central drilling or internal cutting tool is used.

  4. The part is then cut from the stock if no flipping is required. Either it is ready to use or goes under post processing.



Characteristics

  • Machine Parameters:

    • Parameters are mostly set by machine operator during G-code generation.

    • CNC milling machine have large build area up to 2000 x 800 x 100 mm

    • CNC turning machine manufacture parts up to 500 mm.

    • CNC machines work with high accuracy and tolerances up to ±0.025 mm diameter.

    • Typical accuracy when tolerance is not specified ±0.125 mm.

  • Cutting Tools:

    • Different cutting tools are used to create different geometries.

    • For grooves, cavities, machine slots, vertical walls end mill tools used are flat heads, bull head and ball head are used.

    • Ball head tools are used commonly in 5-axis CNC machine.

    • To create holes, drills are used which are available in standard sizes.

    • Plunging flat head end mill tool used following a helical path for non-standard diameters.

    • For T-slot and other under cuts, slot cutter is used. It removes material from sides of vertical wall.

    • Threaded holes are manufactured using threading taps with precise control rotation and tap’s linear speed is needed.

To produce large flat surface area with fewer passes face milling tool is used in early stages to reduce time. They have larger diameter than other end mill tools.

CNC Machine PROs and CONs

Pros

  • Ideal for high end application for its great accuracy, repeatability and tolerance.

  • CNC materials are suitable for most engineering applications and are isotropic in nature.

  • Cost effective for prototyping and up to 1000 units.

Cons

  • CNC use subtractive technology by removing extra material and can’t manufacture certain geometries.

  • Less suitable for low cost prototyping and high start-up cost.

  • Lead timing is more.



FDM (Fused Deposition Modeling)

 

Property

Industrial FDM

Desktop FDM

Standard accuracy

+- 0.15% (lower limit +- 0.2 mm)

+-% (lower limit: +- 1.0 mm)

Typical layer thickness

0.18 – 0.5 mm

0.10 - 0.25 mm

Minimum wall thickness

1 mm

0.8 -1 mm

Maximum build envelope

Large (e.g. 900 x 600 x 900mm)

Medium (e.g. 200 x 200 x 200 mm)

Common materials

ABS , PC , ULTEM

PLA, ABS, PETG

Support material

Water - soluble

Same as part  (typically)

Production Capabilities (per machine )

Low/Medium

Low

Machine cost

$50000+

$500 -$ 5000

  • The geometric tolerances and part accuracy are dependent upon printer calibration and model complexity.

  • Advanced features (i.e. calibration algorithms, heated chamber, higher printing temperatures and dual extrusion)

  • High dimension accuracy – tolerance of ± 0.5 mm.

  • Minimum feature size – approx. 1mm.

  • Industrial FDM designed for reliability and repeatability.

  • Desktop FDM needs regular calibration and high maintenance.

  • Suitable for most prototyping, modelling or low-volume manufacturing requirements.

  • No vertical features(z axis) for layer height (0.1-0.2mm)

  • Planer features less than nozzle diameter (0.4-0.5mm)

  • Walls must be 2,3 times larger than nozzle diameter (0.8-1.2mm)

  • For smooth surface and finer details SLA/SLS.

  • FDM is a material extrusion 3d printer.

  • FDM (Fused deposition modelling) or FFF (Fused filament fabrication)

  • Uses thermoplastic polymers as material.


Working of FDM

 

  1. Nozzle after reaching desired temperature receives thermoplastic filament from pre-fitted spool through extrusion head and filament melts.

  2. Extrusion head moves in X, Y and Z direction. On a predetermined location melted material is extruded in thin strands where it get cool to solid structure. Cooling can be accelerated through fans.

  3. On a repetitive process material is deposited layer by layer. After every layer extrusion head moves up or platform goes down. This goes on until completion.

Characteristics

 

Parameters that can be changed:

  • Temperature of nozzle and platform.

  • Build speed.

  • Layer height.

  • Speed of cooling fan.

Build size for Desktop 3d printer: 200x200x200mm

Build size for Industrial 3d printer: 1000x1000x1000mm

Build size can be broken down and then assembled.

  • Typical Layer height: 50 and 400 micron.

  • Smaller layer produces smoother finish and higher details.

  • Larger layer height produce faster cheaper. (200 micron)


Warping

 

  • Deferential cooling build up internal stress which pulls up underlying layer upward causing warp.

How to avoid?

 

  • Increasing adhesion between build platform and the part.

  • Closely monitoring temperature of the build platform and the chamber.

  • Choice of designers to avoid large flat areas, thin pointy features or to add additional material to touch platform. Avoid sharp corners and add fillets.

  • ABS more warp sensitive than PLA, PETG.

Z-axis is weaker than XY-axis.

Layer adhesion between deposited layers is important.

FDM always have wavy surface.


SLA (Stereo Lithography)

Stereo lithography, an additive manufacturing process is from photo polymerization family have different variants according to parts fabricated:

  • Top down

  • Bottom up

  • CLIP

Also similar to DLP (Direct light processing). In DLP, instead of a UV laser, a UV projector is used.

An object is created by a polymer resin layer-by-layer selectively curing using an ultraviolet (UV) laser beam. The materials used in SLA are photosensitive thermoset polymers that come in a liquid form.


Working

  1. The build platform at a distance of one layer height for the surface of the liquid is first positioned in the tank of liquid photopolymer.

  2. A UV laser creates the next layer by selectively curing and solidifying the photopolymer resin. Using set of mirrors called galvos laser is focused on predetermined path and the whole cross section area is scanned of model is scanned to produce fully solid parts.

  3. After finishing a layer the platform moves at a safe distance and sweeper blade re-coats the surface. Process is repeated until the part is complete.

  4. The print is in green and if very high mechanical and thermal properties are required then further post processing under UV light

 

Desktop and Industrial SLA

   

Bottom-up (Desktop) SLA

 

Top-down (Industrial) SLA

   
    

 

     Advantages

 

+ Lower cost

 

+ Widely available

 

+  Very large build size

 

+  Faster build times

 

  

 

   Disadvantages   

 

-    Small Build size

 

-  Smaller material range

 

-  Requires more post-processing

   due to extensive use of support

 

-   Higher coast

 

-   Require specialist operator

-   Changing material involves

         emptying the whole tank

 

Popular SLA Printer                 manufacturers


 
 

Formlabs

 

 

3D Systems

 

Build Size


 
 

Up to 145 x 145 x 175 mm

 

Up to 1500 x 750 x 500 mm

 

Typical layer height

 

25 to 100 microns

 

25 to 100 microns

 

Dimensional Accuracy

 

+- 0.5% (lower limit: +- 0.010 – 0.250 mm)

 

+- 0.15% (lower limit +- 0.010 – 0.030 mm)





 

SLA curing continues even after the completion of the printing process.


Limitations and benefits

 

Pros

  • Can produce prints with intricate details and high dimensional accuracy.

  • Ideal for visual prototypes as they have very smooth surface finish.

  • Material for SLA available are flexible, clear and cast able.

Cons

  • Generally brittle and not suitable for functional prototypes.

  • Visual and mechanical properties will degrade under sunlight.

  • Support structure are required and post processing to remove visual marks left by it.

 

   

Stereolithography  (SLA)

 

   

        Materials

 

Photopolymer resins (thermosets)

 

 

  Dimensional Accuracy

 

+- 0.5 % (lower limit: +- 0.10 mm) - desktop

+- 0.15% (lower limit +- 0.01 mm) – industrial


 
 

  Typical Build Size

 

Up to 145 x 145 x 175 mm – desktop

 

Up to 1500 x 750 x 500 mm – industrial

 

 

Common layer thickness


 
 

 25 – 100  microns

 

Support

 

Always required (essential to producing an accurate part)


SLS (Selective Laser Sintering)
  • It consists of a laser, recoater, bed of powder material which is heated below the temperature of material’s melting point.

  • The system is isolated to surrounding environment.


Working

  1.  

The printing area with powder bin is heated below the melting temperature of powder material. After that power material is spread in a thin layer by recoating blade.

 

  1. A CO2 laser sinters selective particles of a polymer powder which fuses them together.

  2. After a layer is completed, another layer is recoated by blade on the surface. Process is repeated until the model is complete.

  3. The parts are enclosed in unsintered powder and before unpacking the platform needs to cool down which needs around 12 hours.

  4. Cleaning is done through a blasting media or compressed air before post processing.

  5. 50% of SLA material can be reused after recycle.


Characteristics

  • It needs no support structure as unsintered powder itself acts as support.

  • Can freely design complex geometries which are impossible with other technologies.

  • Recoating steps determine the total processing time. Time does not adhere to numbers part it contains in a given height.

  • Isotropic mechanical properties.

 

  •  

 
 

X-Y direction

 

Z direction

Tensile Strength

48 MPa

42 MPa

Tensile Modulus

1650 MPa

1650 MPa

Elongation at break

18%

4%

 


Injection Moulding Materials

Material requirement for mould making

  • High stiffness
  • High temperature resistance
  • High level of details can be added

Mould making materials

  • According to stiffness
  • According to thermal properties
  • According to level of details


  • According to production capabilities

Materials for Injection Moulding





CNC Materials

CNC Material

Practically every engineering grade material can be used in CNC machine. Properties of the material are not changed after CNC machining and remain identical from original material piece. Plastic CNC parts are commonly used for prototyping before mass production by injection moulding due to their lower stiffness and low melting temperature.

Choice of Material according to its properties


Material and its properties

MATERIAL

GRADE

STRENGTH

HARDNESS

MACHINABILITY

COST

TYPICAL

APPLICATION

 

ALUMINIUM

6061

Medium

Medium

â??â??â??â??â??

$

General Purpose

Aircraft components

Automotive parts

Bicycle Frames

Food Containers

6082

Medium

Medium

â??â??â??â??â??

$

General Purpose

Automotive parts

Food Containers

7075

High

Medium

â??â??â??â??

$$$

Aircraft &

Aerospace components

Automotive parts

Marine applications

5083

Medium

Low

â??â??â??â??â??

$$

Marine Applications

Construction

Pressure Vessels

 

STAINLESS

STEEL

304

High

Medium

â??â??

$$$

General Purpose

Medical Devices

Food Industry

Marine Applications

Chemical Processing

316

High

Medium

â??â??

$$$$

Food Preparation

Equipment

Marine Applications

Architecture

Surgical Implants

Chemical Containers

2205

Duplex

High

High

â??

$$$$$

Oil & Gas

Marine Applications

Chemical Processing

Heat Exchange

303

High

High

â??â??â??

$$$$

Aircraft Components

Machine Parts

Nuts, Bolts, Gears,

Bushings

17-4

High

Very High

â??â??

$$$$$

Turbine Blades

Marine Applications

 Chemical Vessels

Oil & Gas

Nuclear Applications

 

MILD STEEL

1018

Medium

Medium

â??â??â??

$$

General Purpose

Machinery Parts

Jigs & Fixtures

1045

Medium

High

â??â??

$$$`

General Purpose

Machinery Parts

A-36

High

Medium

â??â??â??

$$

Constructions

Machinery Parts

Jigs & Fixtures

 

ALLOY STEEL

4140

Medium

High

â??â??

$$$

General Purpose

Machinery  Parts

 Tooling

4340

High

High

â??â??

$$$

Aircraft Landing Gears

Power Transmission

Tooling

MATERIAL

GRADE

STRENGTH

HARDNESS

MACHINABILITY

COST

TYPICAL

APPLICATION

 

TOOL STEEL

D2

High

Very High

â??

$$$$

Cold-working Tooling

Dyes & Stamps

Cutting Tools &Knives

A2

High

Very High

â??

$$$$

Cold-working Tooling

Dyes & Stamps

Cutting Tools &Knives

O2

High

Very High

â??

$$$$

Cold-working Tooling

Dyes & Stamps

 

BRASS

C36000

Medium

Medium

â??â??â??â??â??

$$

Mechanical Parts

Valves & Nozzles

Architecture


Material characteristics

 

  • Aluminium alloys

    • 6061: Good strength to weight ratio, good machinability and most common general use aluminium alloy.

    • 7075: Comparable to steel after heat treatment. Mostly used where weight reduction is critical like aerospace application.

    • 5083: Exceptional resistance to seawater, welding capability and higher strength then most of the other aluminium alloys. Used commonly in marine applications and constructions.

  • Stainless steel

    • 304: Environment condition and corrosive resistant. Most stainless steel alloy with good machinability and mechanical properties.

    • 316: Similar mechanical properties to 304. Often preferred for harsh environment condition due to its high corrosion, chemical and seawater resistance.   

    • 2205 Duplex: Highest and double the strength from other stainless steel alloys with high corrosion resistance having applications in oil and gas industries.

    • 303: High toughness but lower corrosion resistance compared to 304. Manufactured high end nut bolts are used in aerospace industry due to its good machinability.

  • Mild steel

    • 1018: Commonly used mild steel alloy having good machinability and welding ability for general use.

    • 1045: Medium carbon steel with high impact resistance and strength. Also good for machinability and welding ability.

    • A36: Suitable for varies industrial and construction application having good welding ability.

  • Alloy steel

    • 4140: Not recommended for welding but suitable for many industrial application due its good strength and good mechanical properties.

    • 4340: To increase its overall hardness, it can be heat treated and also have welding ability.

  • Tool steel

    • D2: Can retain hardness up to 425o C temperature and with good wear resistance. Used commonly for manufacturing cutting tools.

    • A2: Used to manufacture injection moulding. General purpose tool steel air hardened with elevated temperature and good dimensional stability.

    • O1:  Oil hardened alloy commonly used for knives and cutting tools. Having high hardness of 65 HRC.

  • Brass

    • C36000: Used for volume application due to high tensile strength, natural corrosion resistance and easily machine-able.


FDM Materials

Material Information Basics

Material’s characteristics are graded using these three broad categories:

  1. Mechanical performance

  2. Visual quality

  3. Process

 

  1. Ease of printing:  Bed adhesion, max printing speed, frequency of failure prints, flow accuracy, ease to feed into the printer etc.

  2. Geometrical accuracy(Visual quality):

    • Size accuracy

    • Overhanging part

    • Circular accuracy

    • Right angles

    • Ridges

    • Curved surface

    • Pointy summit

    • Deposition regularity

    • Thickness regularity

    • Warping/expansion

    • Smearing/smudging

Details and textures:

      1. Intricate shape

      2. Thin ridges

      3. Small details

      4. Smooth surface

      5. Textured surface

  1. Max stress: Maximum stress the object can undergo before breaking when pulling it.

  2. Elongation at break: Before breaking how much maximum length did it stretch.

  3. Impact resistance: In a sudden impact how much energy needed to break it.

  4. Layer adhesion: To be isotropic or uniform in all direction there should be good adhesion between layers of material.

  5. Heat resistance: Max temperature sustained by an object before deforming or softening.

  6. Rigidity and essence: Considered only for some application.

  7. Humidity resistance and toxicity.


Scaling of materials

 

Material name

Ease of printing

Visual quality

Max stress

Elongation at break

Impact resistance

Layer adhesion

Heat resistance

PLA

High

good

good

low

low

good

Low

ABS

low

medium

medium

low

medium

low

High

PET

good

medium

low

low

medium

medium

Low

Nylon 6

medium

medium

low

medium

good

low

Low

TPU

low

low

low

high

high

medium

Low

PC

low

medium

high

low

medium

Medium

high

 

(High> good> medium> low)

PLA (Polylactic Acid)

 

PLA is made from fermentation of cellulose and starch like carbohydrates to obtain lactic acid.

PLA properties superior to PBS, PLC, PHB.

PLA prints semi-transparent, which makes it look little glossier.

PLA smells slightly sweet while printing.

PLA less prone to error.

 



ABS (Acrylonitrile Butadiene Styrene)

 

Abs is among most successful thermoplastics.

Abs properties high hardness, strength, high temperature resistance and ease of moulding.

Abs mainly used in automotive application such as knobs, wheel covers, mirror, headlight housing. Refrigerator linings, kitchen appliance housing, vacuum cleaner, power tools, LEGO.

Abs prints with matte finish.

Abs can easily sanded, machined like drilling.

Abs more prone to warping.

Abs must be printed on heated surface.

Abs fumes are unpleasant.

PET (Poly Ethylene Terephthalate)

Nylon 6

TPU (Thermoplastic polyurethane)

PC (Poly Carbonate)


SLA Materials

SLA uses thermoset polymers. By process of photopolymerisation, turn it into hard plastic.

Pros:

  • Smooth surface finish. Can be used for injection moulds.

  • Used for greater quality and finer details.

  • Hard to bend.

Cons:

  • Gets brittle after UV curing

  • Properties changes if used outdoors

  • Prone to creep.

 

Different SLA resins

 

Standard resin

 

  1. Low cost, ideal for prototyping.

  2. Grey resin used for finer details.

  3. White resin used for smoother surface.

  4. Used for concept modeling, rapid prototyping, art model.

Pros:

  • Cost effective

  • Greater details

  • Smoother finish

Cons:

  • Brittle

  • Impact strength low

  • Low heat resistance


 

Minimum Wall Thickness

1 to 3 mm (depending on dimensions)

Minimum Details

0.5 mm

Accuracy

±0.2% (with a lower limit of ±0.2 mm)

Maximum Size

250 x 250 x 235 mm

Clearance

0.3 mm

Interlocking or Enclosed Parts?

No

 

Mammoth resin

 

  1. Suitable for creating bigger prints

  2. Medium mechanical resistance

  3. Used for printing very large models


 

Minimum Wall Thickness

1 to 3 mm (depending on dimensions)

Minimum Details

0.5 mm

Accuracy

±0.2% (with a lower limit of ±0.2 mm)

Maximum Size

2100 x 700 x 800 mm

Clearance

0.3 mm

Interlocking or Enclosed Parts?

No


Clear resin

 

  1. Similar mechanical properties to standard resin.

  2. Optically transparent after post processing.

  3. Used in LED housing, devices showcasing internal features and fluidic devices.

Pros:

  • Transparent

  • Smooth finish

  • High details

Cons:

  • Brittle

  • Impact strength low

  • Clarity may decrease under sunlight


 

Minimum Wall Thickness

1 to 3 mm (depending on dimensions)

Minimum Details

0.5 mm

Accuracy

±0.2% (with a lower limit of ±0.2 mm)

Maximum Size

2100 x 700 x 800 mm

Clearance

0.3 mm

Interlocking or Enclosed Parts?

No


SLA materials for Engineering purpose

 

Tough resin

 

  1. Similar like ABS

  2. Tensile strength 55.7 MPa

  3. Modulus of elasticity 2.7 GPa

  4. Sturdy, shatter resistant

  5. Used for functional prototypes and mechanical assemblies.

Pros:

  • High stiffness

  • Repeated load

Cons:

  • Brittle

  • Low temperature resistivity

  • Cannot build wall length less than 1 mm wall thickness

 

Durable resin

 

  1. Similar mechanical properties to PP (Polypropylene)

  2. Used for functional prototypes, consumer products, low friction and wear mechanical parts.

Pros:

  • High elongation break, flexibility

  • Tougher impact resistance than tough resin

  • Wear resistance is high

Cons:

  • Cannot build wall length less than 1 mm thickness

  • Low heat resistance

  • Lower tensile strength than tough resin

 

Heat resistant resin

 

  1. Operate at high temperature

  2. Used heat resistant  mold prototyping, casting and thermoforming tooling.

Pros:

  • High heat resistance

  • Surface finish is smoother

Cons:

  • Brittle

  • Cannot build wall length less than 1 mm thickness.

 

Rubber Like resin

 

  1. Rubber like soft to touch

  2. Used for prints suited for bent and compressed and  wearables prototyping, multi-material assemblies, handles, grips, overmolds.

 

Pros:

  • Impact resistance is high

  • Simulates rubber with 80A durometer

  • Elongation is high

Cons:

  • Less heat resistant and UV resistant

  • Support is required extensively

  • Don’t have properties of tree rubber

  • Cannot build wall length less than 1 mm thickness

 

Ceramic filled resin

 

  1. Reinforced with glass or ceramic particles.

  2. Used suitably for thin wall features molds and tooling, jigs, manifolds, fixtures, housings for electrical and automotive applications.

Pros:

  • High modulus of elasticity.

  • High heat resistance

  • Finer details and tough resin

Cons:

  • Brittle

  • Impact strength is low

 


SLS Materials

 

Glass Filled Nylon

  • Also known as PA3200.

  • It is a reinforced material, polyamide-12 and 30% glass filled.

  • Grainy surface and white in colour.

  • High stiffness and mechanical wear resistance

  • Good thermal load ability and low abrasive quality

  • Slightly porous in nature due to its powder form.

  • Parts can be dyed and painted

  • Dyeing does not add any surface thickness as it is absorbed in by pores

  • Painting adds 100-200 micro meter

  • Painting is not recommended on functional and mechanical parts.

  • Has dull white colour

  • Used in automotive industries, functional parts and complex geometry designs.

 



Polyamide

  • Polyamide can resist certain amount of impact degree and is slightly flexible.

  • Can be rigid or flexible according to requirement.

  • Slightly porous and surface is granular and sandy.

  • Used for complex models, architectural models, functional models.

Design Specifications

 

Minimum Wall Thickness

0.8 to 1 mm

Minimum Details

0.3 mm

Accuracy

±0.3% (with a lower limit of ±0.3 mm)

Maximum Size

650 x 330 x 560 mm (natural) 650 x 330 x 560 mm (spray painted) 200 x 200 x 200 mm (polished) 270 x 150 x 150 mm (dyed) 400 x 400 x 330 mm (dyed black) 200 x 150 x 150 mm (polished and dyed) 200 x 150 x 150 mm (satin) 150 x 150 x 150 mm (velvet) 200 x 150 x 150 mm (priority) 300 x 300 x 300 mm (waterproof white)

Clearance

0.5 mm

Interlocking or Enclosed Parts?  

Yes



Nylon

  • Also known as PA2200 is a compound of polyamide.

  • White in colour

  • Granular surface finish

  • High elongation break and mechanical properties.

  • High flexibility due to lower flexural modulus.

  • Food safe except high alcoholic contents.

  • For storing liquid content epoxy like coating is needed in post processing. As nylon is porous in nature.

  • Suitable allowance should be given to critical functional parts for painting.

  • Painting adds 100-200 micro meter.

  • Used in snap fit assemblies, mechanical parts and medical industry where it comes in direct contact to our skin.

  • Natural white colour may fade after some usage.


Injection Moulding Design

Part designing with Injection Moulding

Important guidelines to consider:

  • Same and uniform wall thickness around whole part, where 1.2 mm to 3 mm is typically used.
  • Using thin ribs and hollowing dense sections to increase strength but avoiding any deformation.
  • Angle of draft should be at least 2o to all vertical parts for no drag marks and 5o angle for 50 mm around taller features.
  • Rounding all the edges and ensuring thickness is consistent throughout even in corners.

 




SLS Designs
  • Does not need support structure.
  • Result solidified product is kept in ambient container filler with unsintered powder.




Design Applications

  • For better surface quality, finer layer thickness can used but it will increase the lapse and cost.
  • For painting the minimum layer should be 100 to 200 micrometer. Whereas painting is not suitable for functional and assembly parts without allowance.
  • To avoid shrinkage and warping in SLS parts should be cooled down slowly.


 

  • Considering 3 to 3.5% shrinkage designing must be done.
  • Adding ribs to large flat surface to reduce the chances of warping
  • During printing stage part orientation can reduce chances of warping.      

Cons and Limitations

  • Small variation in same design can occur on different batches.
  • For smooth finish post processing is required as SLS produces grainy matte finish on surface.

Consideration of parameters while designing



SLA Designs

Most print parameters are fixed by manufacturer other than layer height and part orientation.

  • Typical layer height ranges from 25 to 100 microns.

  • A low layer height captures curved geometries more accurately but increase time, cost and failure probability.

  • 100 micron suitable for most applications.

  • Support structure is always needed in SLA and are printing in same material.

  • Visually critical parts should not come in contact of support structure.

  • Curling (similar to warping) occurs when considerable shrinkage of resin under light brings internal stress between new and previous layer.

  • They have isotropic mechanical properties.

  • SLA parts must be post cured under intense UV light to achieve more hardness and temperature resistivity. It also makes it brittle.

  • Minimizing cross-sectional area in Z-axis




  • Minimum size of print will be the spot size of laser

  • SLA by default prints solid which can be changed to hollowing

  • Hollowing the model when it not functional reduces material used, time and cost.

  • For uncured resin, a drainage hole must be added.

  • Uncured resin can cause cupping due to pressure imbalance.

  • One hole of minimum 3.5 mm diameter must be added to every hollow section.



FDM Designs

Bridging

Printing between two anchor or support points.

  • To avoid sagging include support.

  • Other than 5mm bridge’s marks of support remains.

  • Splitting the design and later post processing can be done.

Vertical Holes

Compression from nozzle deforms the extruded round layer shape into flatter shape causing increase of extruded segment width.

  • Depends upon the slicing program.

  • Accuracy can vary and several test prints could be required for desired result.

  • Printing it undersize and then drilling hole should be considered for critical diameter vertical axis hole.


Overhangs

Overhangs occur when the printed layer of material is only partially supported by the layer below. Inadequate support provided by the surface below the build layer can result in poor layer adhesion, bulging or curling.

  • For 45 degree above support is must.

  • When newly printed layer becomes increasingly thinner at the edges at the overhang. Curling occurs due to differential cooling causing it to deform upwards.

Corners

Features can never be perfectly square as FDM nozzle is circular. Compressing material often causing flare called “elephant foot”.

Vertical Pins

Small pins may not print at all as there is not enough print material for newly printed material for the newly printed layers to adhere.

  • Often do correct print calibration (optimal layer height, print speed, nozzle temperature.)

  • Addition of radius at base reduce chances of stress concentration and add strength.

  • For pins smaller than 5mm diameter, add small fillet at the base of the pin.

  • For critical function, add off the shelf pin by inserting it into hole drilled of correct size.

Splitting up your model

To reduce complexity, saving on cost and time, overhangs are split into sections. They are individually printed and then glued together once print is complete.

Hole Orientation

Re-orientation of horizontal axis holes can eliminate the need for support.

Build Direction

FDM is anisotropic in nature and is weak in one direction. According to application it’s built direction is critical. Printed layer are round end rectangles where between joints are small valley structure. This creates a stress concentration where crack can form.


Support Structure

  • Some geometries require structure. Like overhang, bulge

  • Designing should be done such way to minimize support structure.

  • Support structure can be of same material or a dissolvable material.

  • Dissolvable require dual extrusion and are costlier.

Infill and Shell Thickness

FDM parts are usually not printed solid to fasten up printing by compromising strength.

  • Shell is outer perimeter wall.

  • Infill is internal structure. Can be low/high density.

  • Default setting is 25% infill and 1mm shell thickness.

Shell

  • Strength can be added by increasing shell thickness.

  • For post processing like sanding, chemical smoothing increasing shell thickness is necessary.

  • Increasing shell thickness increases overall time and cost.

  • To prevent voids design shells to be multiple of nozzle diameter.

Infill

  • FDM printers are typically printed with low density

  • Increasing infill percentage (25% to 50% to 75%) increases strength.

Feature Strength

  • The base of a snapfit connection is often a weak point. With a low infill density (20%) the cantilever is much more likely to break as the short extruded clip is only connected to a the body of print by a small cross sectional area.

Screwing, Taping and bolting

  • Higher infill desirable minimum 50%.

 

 

  • When screwing into a part increase shell thickness or infill percentage to improve anchoring. If this is not possible, consider using a clearance hole and bolting (with washers).
  • For cheap rapid prints rectangular infill it the best selection due to its quick print speed. If strength is critical to the function of a 3D printed part honeycomb or triangular infill offer an increase in strength when compared to rectangular infill.


CNC Design

Technical Drawing

3D CAD model file is used for programming CNC machine and for reference while machining process. Parts can also be directly manufactured using technical drawing to save time. As long as most important measurement such as of the threads are mentioned.

Technical drawing anatomy:

  • A title block:  Basic information about function of the part. Technical information such as scale, dimensioning standards and tolerance. Also angle projection is added to determine the way the views are arranged.                                                                               
  • Pictorial and isometric view of the parts:  Undistorted presentation of parts geometry.



  • Orthographic views of the part:  2D depiction of 3D object which conveys most information about geometry of the part. Typically 2-3 orthographic views are sufficient to describe the whole geometry.

  • Detail sectional view of the part: To show internal details, sectional view is used. Cross hatch pattern denotes removed
    material and the cutting line in orthographic view shows where the cross section area is.



(Sectional view)

(Detail view)

  • Manufacturer’s notes: For additional information to manufacturer, notes are added.


SLA Post Processing

Basic Support Removal

  1. Support structure is removed by cutting it off
  2. For visually critical area, post processing such as sanding is needed.

After Effects

  • Overall geometry and accuracy of model is not changed.
  • Clean finishing with high precision is needed.
  • Aesthetically can be unpleasing
  • Vertical hole drilling for critical diameter should be done after printing.

Sanded Support nibs

  1. Used for flatter surface models.
  2. Small support nibs are removed.

After effects 

  • Matte finish hides the imperfections.
  • Non-uniform sanding can results in uneven surface.
  • Not suitable for clear resin aesthetic appeal.

 

Wet Sanded

  1. Generally used to get smoothest finish
  2. Unsupported side can be done using single grade of sand paper
  3. Side with support require at least 4 grade of sand and more labour.

After Effects

  • Accuracy of sanded parts may hinder.
  • Very smooth surface finish.
  • Print can get spots by water during wet sanding
  • Surface preparation is good for painting.
  • Complex geometry results are good.

Mineral Oil Finish

  1. Sanding is done using mineral oil instead of water.
  2. Mineral oil helps lubricating and solved friction problem in mechanical parts.

After Effects

  • Surface is not suitable for painting
  • Brings semi-transparent finish to clear resin.

Spray Paint

  1. Uses UV protected acrylic.
  2. Spray painting masks support removal lines and save the time to sand.

After effects

  • Affects the details and tolerance of model.
  • Increases overall dimensions
  • Protect from UV
  • Protect from yellowing
  • Finishing for complex geometry is cleared
  • Not suitable for flexible resin with critical dimensions
  • Not suitable for mechanical parts

Polishing

  1. Polishing is done to get clear transparent finish.
  2. Sanding is done by gradually increasing grit up to 2000 grit.
  3. After sanding surface is polished using polishing materials and compound.

After effects

  • Clear resin gets glass like finish
  • Not suitable for tough and flexible resin
  • Surface gets very smooth

SLS Post Processing

Common SLS Post Processing

  • Standard finish
  • Media Tumbled (Vibro polish)
  • Dyeing
  • Painting
  • Nickel plating

Improvements due to post processing

  • UV protection
  • Chemical resistance
  • Decreased gas permeability
  • Colour protection
  • Increased wear resistance
  • Oil- and (salt) water resistance

Standard Finish

  • Unsintered powder is removed through compressed air and later by plastic bead blasting.
  • After standard finish the surface is similar to medium grit sand paper with matte finish.

After Effects   

  • This is a standard finish for every SLS print
  • Geometry overall remains same
  • Cost effective
  • Grainy surface with matte finish.
  • Limited colouring options.

Media Tumbled (Vibro polish)

  • Polishing is done in vibro machine or media tumbler.
  • It is done by ceramic beads or chips which vibrate against the surface for polishing

After Effects

  • Rounding of sharp edges hinders accuracy
  • Delicate features may differ
  • Can do multiple parts at once
  • Very smooth surface finish.

Dyeing

  • Emerged hot colour bath.
  • Porous SLS surface absorbs colour dye up to 0.5 mm.
  • Dyeing is a fastest and cost effective method for colouring.

After Effects

  • Does not affect dimensions
  • Multiple dyeing colour of parts can be done at once
  • Complex geometries accuracy remains same
  • Variety of colours are large to choose
  • Not gives glossy finish
  • Penetration of dye is up to 0.5 mm.

Spray painting and lacquering

  • SLS prints can be coated with spray paint.
  • Varnish coat aka lacquering is also possible
  • Lacquering improves surface hardness, glossy finish, water tightness, wear resistance and smudge marks removal.
  • Multi thin layer of coat instead of one thick layer.

After Effects

  • Mechanical properties are improved via varnishing
  • Impacts overall accuracy
  • Increases UV protection
  • Glossy smooth surface
  • Time consuming

Water tightness

  • Various materials are applied to SLS parts to make it water resistant
  • Polyurethane (PU) is not used for SLS
  • Coating of silicon and vinyl-acrylates are applied to get the best result.

After Effects

  • Improves water resistance
  • Mechanical strength is also improved
  • Thick coating differs overall accuracy

FDM Post Processing

Support removal using:

  1. Dental pick set
  2. Needle nose pliers
    • Dental pick and needle go into places like holes to remove extra.
      • Pros: quick, don’t change overall geometry.
      • Cons: remains layer lines, if excess material left behind it reduces accuracy.

Dissolvable support removal:

  1. Solvent safe container
  2. Solvent
  3. Ultrasonic cleaner(optional)
    • Dissolvable parts kept in solvent until dissolved. (use warm solvent to fasten up if no ultrasonic cleaner)
      • Pros: helps in building complex geometry and smooth surface where support was there.
      • Cons: not remove layer lines, risk of small divot holes leak, improper removal leads to bleaching, warping of the point.

Sanding:

  1. Different grit sandpaper start from 150 to 2000.
  2. Tack cloth.
  3. Toothbrush
  4. Soap
  5. Facemask
    • Sanding is done to remove support marks blobs. Gradually increase the grid according to height of micron. Recommended to wet sand the print. Clean it with a toothbrush and soap then tack cloth. Always sand in small circular motion.
      • Pros: produce extremely smooth finish, makes painting, polishing, smoothing, epoxy coating very simple.
      • Cons: not for 2 or less perimeter shell, difficult for intricate and small detail surface. Can effect accuracy if done aggressively too much removed.

Cold welding:

  1. Acetone
  2. Foam applicator.
    • When size exceeds from printer size, they are broken into sections and later assembled. Abs can be welded using acetone, lightly brushed on surface and tightly held. Chemical bonded. Interlocking joints increase surface area for acetone.
      • Pros: acetone won’t alter color much, after dry joint exhibits abs properties
      • Cons: welded by acetone joints not as much strong than single piece, excess acetone dissolve the parts.

Gap filling:

  1. Epoxy resin(for small voids)
  2. Auto body filler(for large voids and joints)
  3. Abs filament and acetone( only for abs)
    • After sanding, to fill gaps emerged during print with Epoxy (xtc-3d). Larger gaps are filled with autobody fillers and require sanding after dry then painted and is strong. Gaps in abs can be filled by slurry of abs filament and acetone with 1:2 ratio.
      • Pros: epoxies are easily sanded and primed, abs slurry is same color.
      • Cons: Autobody fillers dry opaquely and form discolor, need additional sanding.

Polishing:

  1. Plastic polishing compound
  2. 2000 grit sand paper
  3. Tack cloth
  4. Toothbrush
  5. Buffing wheel or microfiber cloth.
    • After sanding polishing provide mirror like finish. Clean it in warm water bath with toothbrush after 2000grit. Wipe with tack cloth. After dry buff with buffing wheel or by hand using microfiber cloth and plastic polishing compound such as blue rogue.

CNC Post Processing

To remove visible tool marks and to smoothen surface and to increase wear, corrosion, chemical resistance various post processing methods are used.


Bead Blasting

  • The part is bombarded with small glass beads, which come in various size courses like sand paper grits. Critical holes can be covered for keeping its accuracy unchanged. Can be done on all materials.

Anodizing

  • An electrically nonconductive and high hardness anodic coating adds thin ceramic layer on surface which can be dyed in different colours.

Anodizing type II

  • Comes clear or in colour
  • Adds up to 25 micro meter layer. Typical 8-12.

Anodizing type III

  • Adds up to 125 micro meter layer. Typical 50.
  • Higher corrosion and wear resistance.
  • Cost is higher. 

Powder Coating

  • Adding of thin protective polymer layer on the surface. A dry paint which typically adds thickness of 18 to 72 micro meter. Available in various colours, it provides impact resistance, wear and corrosion resistance. Compatible with all materials but faces problem when applied to internal surface.
  • Curing is done at 200oC temperature after spray painting.

Heat Treatment

  1. Before CNC Machining
  2. After CNC Machining

Common Heat Treatment Methods

  • Annealing: After heating metal at very high temperature it is slowly cooled down for achieving desired microstructure. Done to improve machinability before CNC machining and can be applied to any metal alloy.
  • Stress relieving: Usually employed after CNC machining by heating the part on high temperature but lower than annealing to remove residual stress created from manufacturing process. Can be applied to all metal alloys.
  • Tempering: Employed after quenching process in which heating is done lower than annealing. It improves mechanical performance and reduces brittleness. Can be applied to Mild steels (1045, A36), Alloy steels (4140, 4240) and Tool steels (A2).
  • Quenching: A metal is heated at very high temperature and then rapidly cooled by dipping it into either oil, water or steam of cool air. Quenching is usually the final process to increase the hardness. Process is compatible with Mild steels (1045, A36), Alloy steels (4140, 4240) and Tool steels (D2, A2, O1).
  • Precipitation hardening or aging: To remove discrete particles and make them dissolve uniformly under metal matrix, the metal aging is done. First metal is heated at high temperature, then quenched. Precipitation hardening is done after quenching where metal is heated at lower temperature for longer duration of time.
  • Compatible with aluminium alloys (6061-T6, 6068-T6, 7075-T6) and stainless steel (17-4).

  • Case Hardening and carburizing: Heat treatment where the aim is to bring hardness on the surface and material inside remains soft. Whereas carburizing involves heating of mild steel in carbon rich environment and then quenched. Used for Mild steels (1018, A36).

Injection Moulding Post Processing

For Higher end precision, post processing is done to trim away after the runner system. Also certain techniques for mould manufacturing are used for different requirement standards.