We got our Second Project just before Christmas, an introduction to laser Technologies.
During our induction week we looked at lazer cutting.
-We where given the dimensions of
148.5mm x 84mm in perspex to create a 3D Christmas decoration of our choice.
We also had to use two of the following techniques , lazer cut, engraved or raster.
I began by drawing out a box with the dimensions about in rhino so i could work freely in the box to create my design. I decided to make a ginger bread house cut out with engraved roof tiles.
We then had to specify the cuts and engravings, so RED was used for the outside cuts and BLUE for the engraving (only RBG colours recognized).
-We then ventured down to the Tech Hub where we were showed the lazer scanning machine and each had a go at scanning a roman styled vase in to the computer programme.
Quite a lenghly process with all the detail the vase had, you have to go over it a couple of times to pick up every individual surface.
We were shown how to scan and manipulate real-world objects and collect data on their shapes using laser technology to replicate single components. This data can then be used to create a computer 3D model suitable for a wide variety of uses such as sculpture or models . With further knowledge i can hopfully learn how to successfully reduce or increase the scale using CAD software to produce an STL suitable for building a model on the solid scape or envisiontech for casting.
- Then we had a day in the tech lab learning about laser sintering and the impact on the industry:
''An additive manufacturing layer technology, SLS involves the use of a high power laser (for example, a carbon dioxide laser) to fuse small particles of plastic, metal, ceramic, or glass powders into a mass that has a desired three-dimensional shape. The laser selectively fuses powdered material by scanning cross-sections generated from a 3-D digital description of the part (for example from a CAD file or scan data) on the surface of a powder bed. After each cross-section is scanned, the powder bed is lowered by one layer thickness, a new layer of material is applied on top, and the process is repeated until the part is completed.
Because finished part density depends on peak laser power, rather than laser duration, a SLS machine typically uses a pulsed laser. The SLS machine preheats the bulk powder material in the powder bed somewhat below its melting point, to make it easier for the laser to raise the temperature of the selected regions the rest of the way to the melting point.
In contrast with some other additive manufacturing processes, such as stereolithography (SLA) and fused deposition modeling (FDM), which most often require special support structures to fabricate overhanging designs, SLS does not need a separate feeder for support material because the part being constructed is surrounded by unsintered powder at all times, this allows for the construction of previously impossible geometries.
Also, since the machine's chamber is always filled with powder material the fabrication of multiple parts has a far lower impact on the overall difficulty and price of the design because through a technique known as 'Nesting' multiple parts can be positioned to fit within the boundaries of the machine. One design aspect which should be observed however is that with SLS it is 'impossible' to fabricate a hollow but fully enclosed element. This is because the unsintered powder within the element can't be drained.''
We were shown the Precious M 080 sintering machine in the lab using 18ct gold, it was creating layers bit by bit to create a delicate golden sailing ship. This precise detail could not be achieved using casting methods.
So now intricate designs that were before too time consuming to be commercially viable for producing can now be created from the initial design to the finished product in a single day!which is pretty impressive. And without the need for a time consuming production process before hand.
The machine brings the ability to switly build prototype models, test and change the design, without the requirement for tooling or molds.The capability to manufacture these designs in a lightweight hollow form that could only previously be executed solid, can deliver significant savings on raw materials in the long run.
Although it is quite expensive at the moment for myself to create a one off piece!
We then had a quick tutorial on Tsplines and created a heart shaped ring,
After have a play with the software, making the ring ect.
We were asked to make a piece that could move straight after the sintering, to be designed on rhino tspines and to be sent to Didgets to Widgets in London where we would go for the day to see how there machines work. They dontuse metal powders in their machines but Nylon , and in various colours too.
Nylon has many benefits along with being ultra light weight, it is very durable and flexible. It can also be sprayed different colours and then heat treated as a finish.
It can also be electroplated to give it a metallic finish.
Below is the piece is the piece i submitted to didgets to widgets, i put some lichen type bits on it from my previous ring i designed to see how the organic shape would come out liked in nylon.
It has a cage enclosing a movable sphere, it printed out directly and could move straight away.
-We then went on to look at lasor engraving with Rhianne from Geti which gave me a real insight into how the machinery works and the cost implication of engraving.
Vector line engraving
This works in a similar way to cutting, but instead of slicing right through the material, the laser just marks the surface.
The laser will trace along the engraving line in Coral draw.
There are three different strengths available: light, medium and heavy – with corresponding depth and darkness.
All three are very thin – approximately the width of the laser's beam.
Stroke width in the Object Properties window, set the stroke width by clicking inside the 'Width' field and typing '0.01mm', then press enter:
Raster fill engraving
Most of the time raster fill engraving is used for filled areas, but you can also raster engrave a line with an outline width above 0.3mm , this is what i used for my paisley pattern on my ring.
Rastering line thinner than this is not likely to produce a good finish.
The strength of rastering varies from black as the heaviest cut
, down to light gray which is the lightest (or white, which is none).
You can use any measure in between these two, as long as all your RGB values match.
Only use the unifrom fill option with no patterns/textures. To give you're engraving a clean cut combine this with vector cuts around the outside of the pattern.
Heavy raster fill engraving ,fill color to black with RGB values of 0, 0, 0
Below is the Silver ring with the paisley engraving, using the raster cut so not very deep.
The Engraving cost £50.
I wouldn't of thought that this could be very cost effective for a plain silver ring but maybe in a statement gold pendant where you could at least make some money back.
For this induction we were given rubbish non usable castings from Andy and we had to laser weld a setting prong back onto the four prong setting on a silver ring.
The laser welding of precious metals offers high quality invisible joining in platinum, palladium, gold, silver, titanium and various other metals.
Using filler wires of the same material, strong joints and repairs to the pieces can be achieved without compromising quality or speed. The repair of damaged jewelry without unseeing heat-sensitive stones makes the task easier and faster by laser.
The only way to break through silver’s surface tension is by using optimal settings on your laser welder. The machine must be capable of 6 or higher kilowatts of peak pulse power for silver.And
it generally takes longer to weld silver than gold or platinum. Using 1.5 to 2 hertz and keeping the heat on the piece while you are working, Avoid stopping and starting because the piece will lose heat, which is necessary for metal flow,
On the ring casting, which was silver i used