Wednesday, November 21, 2012

sorry it has been so long

Although this entry is a bit broken here is some of the things I have been doing and have been done by others since last time I published. Pics to follow sorry it has been so long.
The issues that I am having
Most plotting programs use .dxf so I assumed that this would be a good file to use as the input file type for the programme to rearrange the segments, and also I was hoping to use AutoCAD to plot out the patterns.the way AutoCAD finds printer drivers is that it locates them through the windows printer manager unfortunately most plotters work directly from built-in drivers from the programme that they utilise to cut patterns, so there is no Windows driver to begin with.

Issues that have been solved
Since I last wrote in this blog an awful lot has gone on, firstly the programming for the segments layouts via rapid pro has been worked on by John Foster there are some examples of what he has achieved below.
Initial STL file And here is the file that the slices derive from.
I have tried to make it as easy as possible for John however in my own confuse fashion have made it more difficult for him sorry about that. I was being a little lazy and relying too much on John's programming to try and sove both the issues with the file type, and connecting up the plotter, the file type I am sticking with SVG and I am generating these files with SVGmaker V3. I need a program in the short-term which cuts out the SVG files that I am creating. For this I am using WinPCSIGN Basic 2012

How the sheets will be laminated together.
There is also use of a piercing wheel to pierce the vinyl, helps vacuum take-hold, as vinyl is not porous.
The first models were produced with silicone spray as divider, however simple soft soap will work better when the sheets are in the vacuum press, the glue on the back of the vinyl will not stick until the liquid has evacuated the space. So the sheet will be perfectly flat before they stick together, the soft soap both acts as a divider for the glue and lubrication for the vinyl.
1. Apply transfer tape adhesive, slightly bigger than the page that is being used, to base of vacuum press [sticky side up] tape the corners of transfer tape to the press.
 2. Cut straight through the vinyl and backing paper where the guide pegs will hold pages into place, (this will be done either by the vinyl cutter or punched out by a hole cutter) depending on program used to cut vinyl.
 3. Remove unwanted vinyl by hand to first page,
 4. Apply soft soap to transfer tape (simply for lubrication on this layer)     
 5. Apply first page face down in vacuum press on top of transfer tape. Guide Pegs will be laminated on transfer tape as well.
It is important at this stage to realise that the soft soap will squeeze off from the sticky side under pressure and Pool in the gaps from the removal of the pieces of vinyl I did not want. The silica paper will not stretch under pressure and will give the vinyl the support that it needs.
6. Peel of backing silica paper,
7. Apply mould release (soft soap) to adhesive in exposed areas
8. Apply second page
9. Put in vacuum press
10. Repeat for additional layers.
When peeling off the silica backing from the page, the unwanted pieces of vinyl should come off on the silica paper. The exception to this is the screw thread, it will need unwanted vinyl to be removed by hand on every page because of the way the object meet's different layers.
11. Once all the pages are laminated together do not remove the last top sheet of silica backing.
12.Use a craft knife and cut down the silica backing, so you are cutting columns also cut down the transfer tape on the bottom row. you will end up with several laminated sandwiches, with silica paper as the top crust and transfer tape as the bottom.
13. Peel off silica paper from column on furthest right. Pickup column on  the left side and peel off tansfer tape, use soft soap and stack columes from right to left, until you have one single colume.
14. Repeat this process for segments and you will have a 3D object.
Issues that need some work
I am tired of constantly plumbing in my plotter to a computer, it never seems straightforward. Although WinPCSIGN Basic works well enough [not perfectly] I still would like an easier solution. I am investigating inkscape and an add-on called inkcut, inkcut is Linux-based my plan is to load both inkscape and inkcut onto a raspberry pi and make inkscape a portable app for my pc.

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