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Lawson Documentation
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Lawson

Release status: concept

Description
Lawson is a printer designed to have high accuracy, precision, and mechanical stiffness.
License
Author
Contributors
Based-on
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CAD Models
External Link


Introduction

Lawson is a high precision and mechanically stiff 3D printer. Components can be substituted to tailor the printer for higher accuracy and precision, or to lower build costs.

Features

  • Stiff, rigid frame with no play
  • High accuracy and precision
  • Mechanical components can be purchased from two suppliers, minimizing the reliance on a middleman supplier.
  • Components can be substituted to achieve higher quality or lower build costs, appealing to a wide audience.

Specifications

Component λ Variant ϵ Variant
Mechanical parts (exc. motors, electronics, screws) 26 26
Printed parts (exc. motors, electronics, screws) 0 17
Hardware Cost (exc. motors, electronics, screws) $443.41 $369.52
Controller Electronics Almost all RepRap Almost all RepRap
Printing Size 200 x 200 x 240 200 x 200 x 240
Motors 4x NEMA-17 Stepper, 1x NEMA-23 5x NEMA-17 Stepper
Pro High accuracy, speed, stiffness Lower cost, high speed
Con Higher cost Lower mechanical stiffness and accuracy

Overview

Design Goals

Cost

Component Sourcing

X-axis

Y-axis

Overview of the triangular y-axis belt drive mechanism.

The y-axis is a belt driven linear stage powered by a NEMA 23 stepper motor. The axis is constrained by a high quality Misumi linear guide. Compared to y-axes in other designs such as the MendelMax 2, this triangular belt configuration permits higher speed and acceleration values, reduces component costs, and simplifies construction and access to the motor. The NEMA 23 was selected instead of a NEMA 17 because it simplifies mounting and generally has higher performance characteristics.


Z-axis

The z-axis is a lead screw driven linear stage powered by two NEMA 17 stepper motors

File:Lawson-z-axis-closeup.jpg
Close-up of the z-axis which is constrained by V-slot wheels.


Printable Components

A number of Lawson components can be 3D printed to reduce build costs, with the caveat that printed components are less stiff than their metal counterparts. Unlike many other RepRap printers, all printable components are purchasable, but not all purchasable components are printable. This means that individuals without access to 3D printers, or individuals who prefer metal components are able to build a Lawson printer.

Optionally printable components are shown highlighted in blue.



Printed Parts

A number of Lawson components can be 3D printed instead of purchased. However, unlike other 3D printers such as the Prusa i3 and MendelMax, all printed components in the Lawson have off-the-shelf purchasable substitutes. This was done for two reasons. The first reason is that you can obtain higher mechanical stiffness by using metal components instead of printed components, although printed components are still effective. The second reason is that having a purchasable version of each part makes the design more accessible, minimizing the reliance on outside suppliers.

High precision design

The lead screws and linear rail are some of the Lawson's most expensive components. While cheaper components are available, the lead screws are critical to ensuring high accuracy, and the linear rail is key to making the print bed mechanically stiff. Other designs, such as the Prusa i3 or MendelMax 2.0, do not have the same mechanical stiffness that the Lawson printer has.

Electronics

Almost all RepRap electronics such can be used to control the Lawson. Electronics confirmed to be working include the RUBMA Board, Printrboard, GEN7, RAMPS, and Rambo board.