VOL. 21 November ISSUE YEAR 2020
in Vol. 21 - November Issue - Year 2020
Advances in Additive Manufacturing Techniques Wax removal during 3D Printing
Layton machine open sides
When a global leader in the development and manufacture of orthopaedic implants approached Layton Technologies for a solution to an issue resulting from the widespread innovation and increase in additive manufacturing (3D printing), Layton knew that they had the capabilities to assist with this highly complex issue.
The additive manufacturing process in question called for the 3-dimensional printing of parts using two different proprietary wax products.
One of these waxes is used as a support material for the second wax which forms the basis of complex geometry moulds for the orthopaedic implants.
The current process for the removal of the support wax is an extremely labour-intensive process which involves the heating and agitation of a flammable solvent in an open top container using a hot-plate and a magnetic stirrer.
This set-up afforded little control of the flammability hazards associated with heating the solvent and provided the operators with minimal protection from any solvent vapours and fumes.
The melting point of the support wax was identified as only 5 °C higher than the melting point of the mould wax and it was essential that when removing the support wax the mould wax was not altered in any way to preserve the precisely printed geometries.
The client identified the need to improve this process as their requirement using this type of additive manufacturing was increasing rapidly and the current manual set-up had become a bottle neck.
Layton were tasked with developing a streamlined process which removed the labour-intensive nature of the current process, greatly reduced the downtime created by the manual cleaning requirement and guaranteeing an end result together with ensuring that waste solvent which was loaded with support wax was kept to an absolute minimum.
The lengthy project included the following requirements and events
Extensive, customer witnessed, trials were conducted to rationalise the current process into a single stage system utilising a flammable solvent at elevated and very precisely controlled temperatures to ensure the removal of only one type of wax.
Due to the nature of the wax contamination detailed calculations were done by Layton to assess the wax loading of the solvent and the length of time that the solvent in the system could continue processing the product before it was saturated with support wax.
The trials and calculations resulted in the proposal for a bespoke system which not only removed the support wax without affecting the other wax but also reprocessed the solvent to ensure that the waste stream for the system was kept to an absolute minimum.
A comprehensive Technical Proposal was produced to satisfy the concerns that the client had expressed as to the overall ability of the new system to meet the requirements of the project.
The documentation produced by Layton, and the results of the tests conducted were all accepted by the client as an acceptable alternative to the current process.
An extensive Technical Proposal was produced which included for automated processing, this satisfied the concerns that the client had expressed as to the overall ability of the new system to meet the requirements of the project.
Following the issue of the purchase order to Layton their in-house design team produced a comprehensive Design Documentation Package which included a general arrangement diagram, a piping and instrumentation diagram and a functional design specification, a software design specification together with a comprehensive Project Plan.
At the same time as the main system design and manufacture Layton undertook the design, development and manufacture of a specialist fixturing to hold the components and to optimise the cleaning and drying process.
The final design resulted in a new, fully automated, low emission flammable solvent cleaning system complete with Layton’s unique 5-year warranty.
Layton Technologies Limited
Unit 33 Parkhall Business Village
Parkhall Road, Weston Coyney, Staffordshire
ST3 5XA, UK