?

Just to elaborate a bit more before you all go planning layouts using this flexible track this is some way off being a product.

It prints on a base similar to that shown above and all the support material is cost in both print time and material cost and how many you can print at a time is governed by the size of the printers build platform. The above was my first experiment and you could only fit five of them on the build platform. There is no way that would be viable as a product but it left a lot of open space that couldnt be used.

Having proved my daft idea actually worked the print was turned on its side. This had a number of benefits.

• 14 of them now fitted on the build platform.
• There is a lot less support material both in the base and in the skeleton.
• Tuning the skeleton removed even more material whilst leaving it supported.
• Now, in to fluid dynamics rather than models, it also improved the flow of uncurred resin runnin of the print.

It is these prints that the sample track is made from.
Still on the printer, whilst there are now 14 prints of 6 sleepers filling the 145mm x 145mm build platform there is a lot of the 175mm Z axis not being used.
Thus the next plan was vertical

This didn't work entirely. I increased it to 8 sleepers and would go more if it worked but I cut back too much of the supports on one side and the end of the sleepers tended to droop. The program put too much support in other places and added interconnecting stringers that weren't there in the smaller prints. This still might be the way to go if I can sort the support and increase the number of sleepers to utilise the available height. A couple of other things come into play in the printer set up.

• Print Time
• Cycle Time

Print TIme: the printer takes quite a time to print these but arguably you could print twice as many of the half height ones in the same time it took to do the full height ones so on print time alone there isn't a lot in it. Then cycle time become significant.
Cycle Time: Basically, the time it takes to print a set, get them off the machine and reset it. Prints happen quite happily with the printer working unsupervised but when it completes a print its a manual job to take the prints off, clean the build platform and start the next print.? Ideally you want a build time of say 10 hours or alternatively 18+ hours.? With the former you can do two runs a day, with the latter one print a day.

It's very easy to find your day is ruled by the damn thing. At one stage when I was trying to catch up with the Townsend Hook kits I was getting up at stupid O'clock to reset the machine for the next print to get three runs a day out of it. That is the way to madness.

Another consideration is the material. There are 28 different resins available with different characteristics. At the moment I am playing with the standard grey as its the cheaper resin for experimenting with but it is quite brittle and its easy to knock the spike off when threading the rail. Doing it for myself one missing spike doesn't matter but thats not a saleable way forward. Luckily the printer supplier is very supportive and will print samples in different resins as a trial before i commit to one. I suspect this will end up on what they call their durable resin which trades a little in resolution for being a lot more resistant to shocks. What I dont know at the moment is if you can add a pigment because in its raw state its translucent blue.?

Whilst the machine is very flexible in that it can easily swap from one material to another but setting it up for a material for the first time commits you to around a ?450 outlay so you need to be sure..

Its all interesting stuff to experiment with but it is very absorbing and you can lose track of doing the stuff you should be doing to earn a living as its more interesting.

I'll let you know how the experiments go but don't hold your breath waiting for the next installment

Paul