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Overview

This category is for detailing the cost of the components that go into a Metalbot 3D Printer

 Open source 3D metal printing technology is still in it's infancy. We still have yet to build a 'proof of concept' prototype so we don't have clear cost estimates at the moment. We are working towards releasing a Bill of Materials to go with the build guide for Metalbot V1.0. We want to make 3D metal printing extremely accessible, however peoples skill levels and technical abilities vary greatly.

 There are tough design tradeoffs that we need to make in order to build the best 3D Metal Printer possible while at the same time keeping it easy to operate and affordable. Considering that many commercials systems cost well about the $500k mark, this is certainly one of our greatest challenges.

 When discussing cost planing for the project please keep in mind the following guidelines:

  • All efforts should be made to keep this project affordable and accessible to everyone... basically everything that current commercial systems are not!
  • Costs and build time both increase exponentially with the size of the printer (e.g. a bigger powder bed will require a larger laser to sinter more powder which will cost more). For now we are focusing on smaller build volumes.

To talk about project cost and budgets please head over to the Cost Planning Forums and voice you opinion.

Goals

  • Write a detailed BOM to go with the Metalbot Build guide (include places to buy parts and prices).
  • Keep the entire Bill of Materials under 10k> (if you disagree please discuss on the forums)
  • Define a goal build volume

Major Costs

There are quite a few expenses that need to be overcome when developing an Open Source 3D Metal Printer:

Metal Consolidation

  • The first big expense is the consolidation method. This is because the materials used to make lasers are very expensive. Even a simple laser system, for example a Nd:Yag laser, uses ruby which is expensive to fabricate. Another reason is that lasers technology is very complex and requires very precise instruments during manufacture. Everything about them is expensive, therefore they are expensive! The higher power a laser is, the more expensive. Other parts of the laser system such as the laser scanner and laser power supply are also unfortunately expensive.
    • Laser Module
    • Laser Power Supply
    • Laser Scanner
  • Engineering Costs One cost to factor in will be the precision machining that will be required to make the powder roller system. This is because we are dealing with extremely thin layers of powder. Evenness of the powder layers will be crucial to the printing quality.
  • Making a Gas Tight Seal on the Door
  • Machining the Powder Containers and Powder Roller
  • Making a Rack Type Assembly for the Laser Power Supply and Electronics

Software and Electronics

We want to make use of as much open technology as we possibly can. Harware as in PCBs and Components will have to be determined.

  • Components BOM
    • Valve, Roller and Gas control (with arduino)
    • User Interface
    • Interface Between Scanner Software and Slicer Software

Hardware and Frames

  • Metalwork
    • Welding the Frame
    • Metal Racks
    • Z-Axis
    • Argon Tank
    • Gas Proofing
  • Material Handling
    • Powder Input
    • Powder Roller
    • Powder Recycling
  • Machining the Printing Bed and Z-Axis
  • Cladding and Gas Proofing the Entire Assembly with Sheet Metal

Tools

What tools are needed to make a metalbot. Can we provide Metalbot in a kit form?

Consumables

There are also consumables that are required for a functioning Metalbot, these run as follows:

  • Powders e.g. cost of filling the powder bed (dependent on build volume)
  • Argon/Nitrogen Gas (dependent on build chamber volume)
  • Electricity to run the machines

Time

How long will it take for the average enthusiast to put together a machine of his own? What prerequisite technical knowledge does he need and what can we do to reduce the barriers to entry?

 --

We do expect that as the popularity of the project increases there will be 3RD Party suppliers that will provide components at a reduced cost, feeding back into the community and reducing the Bill of Materials cost total.

 

As the project develops the individual parts and subsystems will become more 'part specific'.

Bill of Materials

To be determined

Part Quantity Price
xx xx xx
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Overview

This category is for discussing the hardware that goes into the 3D Metal Printer. This includes the material handling hardware (e.g. powder spreaders and wire feeds).

The Frame: The frame pulls all of the printer subsystems together into one modular design. When printing with materials that are volatile at high temperatures in the presence of oxygen (e.g. Titanium) the frame will need to provide an inert oxygen free atmosphere.

 

The Z-Axis is underneath the build area and must move down a specified amount (under 100 microns) per build layer. This is generally

achieved through a stepper motor and ball screw assembly. This method can achieve very accurate Z-Axis movement. The precision of the

Z-Axis determines the precision of the powder layers and therefore the resolution of the printed part.

 

 

However the Z-Axis and powder roller must be built to very high precision. This is because we are dealing with extremely small layers.

Any uneven parts will cause one section of the powder bed to be thicker than the other disrupting the quality of the printed parts.

Knowledge about machining and metal work will be very useful when building the Metalbot frame. For those who do not have access to machining

equipment, there are many online services that will take CAD data and machine parts to you exact specifications​
Please visit the frame forum to add your thoughts!

To discuss hardware and frame design choices please head over to the Hardware and Frame forum.

Goals

Goal Popular Solutions Status
Frame Material Steel Chassie Pending Community Choice
Gas proofing Metal Cladding Pending Community Choice
Viewing Port Protective Glass/ Internal Camera Pending Community Choice
Inert Atmosphere Argon/Nitrogen Pending Community Choice
Target Layer Thickness <100um Pending Community Approval
Target Granule Size <30um Pending Community Approval
Powder Spreading Mechanism Roller/Blade Pending Community Choice
Powder Handling Motors Stepper Pending Community Approval
Powder Bed Heating More Data Required  
Laser Assembly Mounting Top Down Pending Community Approval
Z-Axis assembly Ball-Screw + Stepper Motor Pending Community Approval

Design Choices

There are a few design choices that need to be made before we can clearly define which direction we want to project to go. To help make these design decisions we can break the Hardware and Frame down even further:

Material Handling

  • Choose the best method of material form: wire vs powder vs ??

 

Frame Design

The frame design serves two purposes:

  • Providing a gas proof environment
  • Physical Housing all of the subsystems

 

 

 

Define a budget for the materiasl handler and frame

The entire printer needs to be modular, this means that the frame design should make it easy to have access to the major components to make it easy for repairs and party replacement (as we are not commercial we can escape planned obselecence). The frame must house the laser, laser power supply, laser scanner head as well as the build area and powder system.​

 

Challenges

Powder System

  • Powder Input
  • Powder Hoppers
    • Single
    • Dual
  • Powder Roller/spreader/blades?
  • Powder/material Recycling
  • Getting an Even Powder Distribution on each Layer
  • Documenting How to Handle Powders Safely
  • Developing an Efficient Powder Recycling System
  • Working out Dimensions for the Powder Containers
  • Powder beds
    • Ceramic vs metal powder beds

 

  • Designing a Gas-Tight Build Chamber
  • Designing a Powder Proof build area and Z-Axes
    • Z-Axis stepper motors (ball screws)
  • Designing a Rack Type System for Enclosing the Equipment
  • Frame Materials
  • Mounting the electronics and metal consolidators
  • Metalwork

Wire Feed

  • Powder Spreading vs Wire feeds

Sourcing Parts and Equipment

If you have found a place to source parts and equipment please add it to the Hardware and Frames parts and Equipment MEGA info Index here: viewtopic$%

This greatly helps toward our eventual bill of materials

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Overview

The software and electronics for the Open Source 3D Metal printer are quite diverse. From driving powder pistons and wire feeds to programming. The software and electronics can be thought of as two main categories

Scanner/Gantry Electronics
Material Handling Electronic

The scanner electronics will need to take the data from a slicer program and convert it into x-y plotting. This information will control

the high speed galvo motors, directing the laser beam to sinter a cross section of the object being printed.

The powder system electronics on the other hand will control the Z-Axis, powder dispenser and powder roller.

We want to make full use of already existing open source software that is avalable so that we dont haveto re-invent the wheel.

To discuss the software and electronics please visit the Software and Electronics forum.

Goals

Goal Popular Solutions Status
Laser Scanner Module More Data Required  
Scanner Card More Data Required  
Scanner Controller Software Beamconstruct Pending Community Approval
Powder Handling Electronics Smoothie Board/Arduino Pending Community Choice
G-Code Slicer sli3er Pending Community Approval

Many of the specific software and electronics design choices will be dependant on the consolidation methods we use.

  • Define how we are going to interface with CAD software.
  • G-Code
  • Cost of parts
  • Smoothie board?
  • Gantry vs Laser scanner
  • Developing a Friendly User Interface
  • Developing and Interface Between the Laser Scanner Software and a Slicer Program
 
Gantry vs Laser Scanner

Laser scanners are the most efficient method for moving a small laser spot over a large surface area. A laser scanner primarily works by reflecting the incoming laser beam between two mirrors.

The combined angle of the mirrors determines the position of the laser beam on the work surface below. The mirrors are attached to special high speed motors called galvanometers. These move at very high speeds and are extremely precise in guiding the laser beam.

Gantries on the other hand are much simpler to construct and many design tips can be gained from the RepRap...

Software & Electronics Challenges

Challenge Status
xx xx

 

  • Developing and Interface Between the Laser Scanner Software and a Slicer Program
  • Controlling the Powder Valves, Powder Roller and Z-Axis timing
  • Developing a Friendly User Interface
  • Controlling the Powder Valves, Powder Roller and Z-Axis timing

Development

To make things easier to manage we can break the software and electronics down into smaller subsystems

Laser Scanners

To direct the laser beam we need to use a laser scanner. ​A laser scanner is made from two mirrors that are connected to special high speed high​ precision motors called galvanometers.​​ Laser scanners are used in many things today, from ​engraving machines to laser projectors.​ The principle that is used for all these applications is the same: software that runs on a PC or an embedded system and that controls the complete process is connected with a scanner card. That card converts the received vector data to movement information which is sent to the scanhead. This scanhead is made up of two mirrors that are able to deflect the laser beam on the X and Y coordinates. The third axes is - if necessary - adjusted by a specific optic that is able to move the laser's focal point in the depth-direction.

There are many commercial laser engravers for metal that are currently on the market with laser powers​ of 50 watts and more.

Sourcing Low Cost Laser Scanners

Defining the Scan Speed

Mounting all of the Hardware

Laser Marking Software

Beam Construct, open source for private use.

 

Sourcing Parts and Equipment

If you have found a place to source parts and equipment please add it to the Software and Electonics parts and Equipment MEGA info Index here: viewtopic$%

This greatly helps toward our eventual bill of materials

 

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Overview

This category deals with joining or fusing layers of metal together.

Metal consolidation is the biggest challenge that faces the Metalbot project. There are many different ways to fuse layers of metal together and each process has its own pros and conns. As a result, we have many design choices to make.

Important Goals include gaining more data on 'laser sintering' and melting of metals. Commercial enterprises are very tight lipped when it comes to their production processes, this means that we need to start from the ground up. Data is good. More data means better design choices so please share you findings on the forums.

General guidelines for designing the metal consolidation system are as follows:

  • Accessible: The components required to consolidate the metals must not be too exotic or difficult to acquire.
  • Affordable: The bill of materials must not blow our target budget.
  • Safe: For mass adoption the printers have to be safe for use by the majority of people. please look at our safety page before getting involved with metal consolidation development.
  • Modular: The system should be easy to maintain or replace worn parts.

Please note: This project is in the very early stages. As the community grows and knowledge increases then our goals and issues will become more specific.

To discuss the subject in-depth with the community please head over to the Metal Consolidation forum.

Consolidation Methods

There many different ways to fuse layers of metal together and each process has its own pros and cons. The consolidation method we have chosen to move the project forward is "laser sintering" or laser melting. Another option that is up for consideration is arc welding, where a hot electric arc is used to melt/fuse wire in an additive way to produce finished parts

Lasers >>

 Pros Cons
Fast when used with a laser scanner Expensive
High accuracy and resolution Dangerous
 Ability use powders to print overhangs Difficult to find
   

 

Arc Welding

 Pros  Cons
 Affordable  Printed parts require milling

Issues

These issues are endemic to any process that repeatedly heats and cools a material. In order for high quality parts to be printed these challenges need to be mitigated.

  • Warping of the Printed Parts due to Shrinkage during Cooling
  • Removing Powder From Enclosed Spaces
  • Powdery Surface Textures of the Finished Part
  • Preventing Powder from Clogging the Moving Parts

Sourcing Parts and Equipment

If you have found a place to source parts and equipment please add it to the Metal Consolidation parts and Equipment MEGA info Index here: viewtopic$%

This will greatly help us toward eventually compiling a bill of materials.

There many different ways to fuse layers of metal together and each process has its own pros and cons. The consolidation method we have chosen to move the project forward is "laser sintering" or laser melting. Another option that is up for consideration is arc welding, where a hot electric arc is used to melt/fuse wire in an additive way to produce finished parts

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Overview

Arc-Wire printing uses a very intense electric arc to melt thin wire. The wire is fed via a wire feeder into the path of the electric arc where it is melted and deposited onto the build surface. This process is the most affordable option to efficiently consolidate layers of metal.

Design Tradeoffs: Unfortunately wire printing does not provide very good printing resolution (in comparison to laser based systems), with welding beads measuring between 1.5-5 times the width of the wire itself. In order to retain part accuracy the weld bead needs to be milled to spec. This requires a milling apparatus to be used in conjunction with the arc welder.

Goals

Wire-Arc Method TIG Accepted
Wire Width ??mm  
Weld pool width 1.5mm Pending
Power Inverter More Data Required ?A Pending
Cooling/Operating Temperature    

 

Development

Arc Head

Tungsten Rod

Gas Shield

Wire Feed

Arc Head Holder

Power Supply

 

Bill of Materials

Part Price (EUR) Qty
Arc Head    
Gas Shield    
Power Inverter    
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