Week 2: Drawing Machines


We will discuss Drawing Machines (Pen Plotters).  And we will check in on our progress on the XY Plotters.


Bot of the Week



Bot of the Week In Action



What is a robot?

What’s your definition?


X, Y, Z axes


We will be working within the Cartesian Coordinate System (3 axes).  Our XYZ Bots can be called Cartesian Robots or Gantry Robots.

X Axis: Left and Right

Y Axis: Front and Back

Z Axis: Up and Down

Typically, the distance traveled in the Z axis is much smaller than the X and Y.


Anatomy of our machines

Gantry – The gantry spans the X axis (left to right) and travels forward and back along the Y axis rails.

Carriage – The carriage travel left to right on the gantry and houses the Z axis

Head (Spindle) – The head is where the work is done.  It typically moves up and down along the Z axis.

Table (Wasteboard) – The table is the work zone.  Items and materials can be fastened to the table.  Those items and materials (even the table) can be manipulated by the head.

– via


Gantry Robot Advantages:

  • 3+ axis of movement of almost any length
  • Scalable
  • Gearbox and motor can be sized according to range of motion and speeds
  • Suitable for light to heavy / hanging loads
  • Flexible and efficient due to linear axes scalability
  • Inexpensive

Gantry Robot Disadvantages:

  • Cannot vary reach into or around obstructions
  • Linear slides belts rails are not easily sealed against the environment
  • Not freestanding: stand or frame or other mounting required



Drawing Machines

Usually the first project with XYZ gantry designs.  One of the most straight forward operations and arguably one of the easiest to perform.  But there are many types of drawing machines out there.





Hello 'bot. What is your name?

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Does it need to be a pen?

Using a pen or pencil can be the right choice, but there can be issues:

  • the correct pressure
  • pen type — ball point, felt, fountain pen
  • paper friction


Other Options

There are other ways to draw.  Consider the following:

More than one

Paint Drip

A post shared by Jeff Leonard (@jeffleonardarts) on

Paint Spray/Air Brush

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Sand Drop

Sand Drag

White Board marker


Dot Peening




Build Session

We will take the rest of class to work on our plotters.  Let’s all download the software and make sure we can get it running on PC laptops.

Download mDraw here:



Our XY Plotters are due next week.  You will have them running/drawing and present them in class.



Related Reading/Viewing

Robot Clock Write Time Over and Over and Over