RoRo Ferry

May 4th.  An attempt to make a perspex version failed, see report.

February 22nd.  This toy is now complete, I will be ordering at least 10 from Stuart at Cut & Burn at some point.  Before I do I will spend hours re-checking the file for errors, they do creep in.

RoRo Ferry, 17cm x 8cm x 10cm, demountable, moving doors

January 19th.  Cut today at Bower Ashton, generally good but I have made some changes: the door ramps now only serve the base deck; the deck curvature is lessened to make assembly easier.  The issue of the engraved press-out bridges is still er, pressing, they need to be uniform around 2mm long but some pieces are very small and cannot accommodate 2mm long bridge.  The depth of the engrave is also critical, they must be deep enough to be easy for child hands to press out, but shallow enough to accommodate variations in the ply thickness and the difficulty in getting the plywood flat on the cutting bed – it is invariably warped.  The most important thing is to eliminate all errors from the file.

January 1st 2017. Completed working on this file, errors removed and it should be cut and returned by the end of this week.

December 16th. Wow. Fast return of the roro from Stuart.   Almost good but too many errors in the file and some design changes needed.  This design is approaching the limits of smallness for 3mm plywood – for one thing the ply is not 3mm, it varies between 2.7mm and 3.4mm which makes accurate mortise and tenon joints tricky, especially as they get smaller.  But a negative result is, empirically speaking a result.

December 14th.  Sent the Illustrator cut file to Stuart at Cut & Burn in Exmouth, he will have a look, correct any obvious mistakes (I hope) and post the cut out 3mm ply back soon as.  Trying to get the cutting cost down to a ‘reasonable’ level, i.e. below £10 per unit, is a real challenge; to really have a cost-effective batch production the laser is not the way.  A metal press is a more likely method (and more like printing) but start-up costs are high.  However I think I have solved the issue of stability (rigidity).

Exploded, 2 deck version, not accurate, not the final drawing
Exploded, 2 deck version, not accurate, not the final drawing

December 12th. Made a cut with Zarya in Fabrication at Bower Ashton.  This revealed in an instant all the things that were still wrong – too big, doors not correct, tolerances too crude, not stable.  In the same instant I had a real insight into how to put things right, so back to the sketch pad and to Illustrator and a couple of days getting a kink in my shoulder blade from hunching over the keyboard, in Illustrator.

November.  Finally began to revise the RoRo, after a long period of neglect. This was mainly due to not having any idea how to stabilise and simplify the design, and how far I could reduce the size yet retain ‘play value’, a rather intangible thing.  I have sketched several ideas and will be booking a cutting session soon.  The cabin has remained the same but it is slightly simpler and is open to the deck so that cars can roll through.  Locking bars are gone as is the mid-deck. But can the main structure be stable?



Tuesday March 29th.  Testing is on-going, but it is clear that I need to make some design changes.  The most obvious step would be to eliminate the middle deck; this would result in lowering the overall height, shortening the ramp doors, improving the access to the interior, simplifying construction.  The superstructure as currently made does not appear to add any play value.  So I intend to revise this, make it ‘useful’ i.e. it will become the lock mechanism for the ramp.  I may add a hoist.  Tolerances in the locking bars must be reduced, the ramp doors must be adjusted to improve their action.

RoRo detail showing ramp door in high position
RoRo detail showing ramp door in high position

Monday Feb 1st 2016.  Successfully cut the second iteration.   Now to test on customer.

Monday January 11th 2016.  At last I managed to make an Illustrator drawing which actually worked.  The actual cutting was straight forward, although Michelle did have to make some fine adjustment when the cutter stopped for no obvious reason.

Cutting the RoRo, first iteration
Cutting the RoRo, first iteration
The assembled RoRo showing one hinge
The assembled RoRo showing one hinge

There were a couple of errors, the cabin slots were not quite right, but overall I am pleased with the result. In the afternoon Andy helped me with 3d printing four more hinges.  Unfortunately these proved to be weak due to printing errors (the temperature of the print is critical) and so had to be done again.

Project_RoRo1-cutting20160111_0008But I have now decided to get rid of the hinges altogether.  This means redesigning the ramp/doors and changing or removing the internal mid-deck ramp.   So, back to the drawing board.

Jan 28th. I have completed the redraw so as to eliminate the plastic hinges.

The changes:

Increase the overall height so that the space between decks is equal.

Top and middle decks have ramps with lattice hinges – only possible with laser cutting.  These may not be robust enough for child use, but worth a try just for aesthetic reasons.

Ramp doors now slide to serve middle and bottom decks.

Thursday November 12th

I have now discovered that sessions in Fabrication can be as short as 1/2 hour and therefore reduce the cost to as little as £4, which is great and which means I can stop pestering the technicians and arrange short sessions.  So I have booked as second laser-cut session for next Friday, 1.30pm to cut the first iteration of the RoRo Ferry.  A sheet of 4mm x 650mm x 800mm is required.

Modelling board 2015
Modelling board 2015

N.B. I have also drawn the Shadow Theatre on paper and begun drawing in 123Design, also trying out a program called EasyDraw.   I cancelled a laser cutting session due to my ill health.  No more sessions were available before Christmas.

Monday October 26th 2015

A laser cutting session booked in advance, each session costs £12 and is for about 1½ hours. I was mainly interested in getting help with Illustrator which Michelle T was able to provide. Having imported my design from Autodesk 123Design into Illustrator I was surprised to find that hundreds of internal ‘construction’ lines were somehow shown in the Illustrator file. It proved necessary to manually remove these, quite tedious.  Illustrator is proving to be tricky, as expected.

I was surprised to learn that I had to bring my own board for cutting rather than buy on site.  But I am now ready for the next session which should be the cutting.

The process of ‘getting to know’ the Fabrication people has not been entirely straightforward, although they are all friendly and helpful they are also all busy and as a part-time, one-day-a-week student it can be difficult to obtain help and advice. I have been into Bower Ashton an additional 6 times so far.


Monday October 19th

I wasn’t able to get the hinge printed last Thursday as there was some problem with the 3d printer; the technicians are going to do it soon as.  I have now got all the RoRo parts on one Rhino sheet, saved in various formats. I’m going to look at the Bower Ashton Fabrication help files today and try to arrange the layout for cutting later this week. Very exciting!  I need to produce an ‘exploded’ drawing as well.

I made the final drawing of the hinge using Autodeak 123D Design, which is currently at the beta stage but is fast and easier than AutoCad, Illustrator or Rhino for a beginner.  Unlike Autocad or Rhino the design can be built up from ‘primitive’ shapes – cylinders, spheres boxes and so on.  After completing the drawing I used Meshes to find and correct any faults or discrepancies.

3d printed hinge, approx 25mm x 40mm x 8mm

I finally got the second attempt at a hinge printed in the brand new 3d suite in Fabrication (Bower Ashton) on Friday October 23rd, with lots of help from Andy.  The .stl file I had was converted by Andy into MakerBot format and he then set the printer (one of three in the suite) and, after an initial failure due to poor plastic on the feed spool the hinge printed.

Andy advised me to wait until it cooled thoroughly…… I almost managed to.

This hinge is acceptable although I might try for a third iteration.  I now need five of them for the first iteration of the RoRo Ferry.

I have decided not to use the hinge in any of the plywood toys, so it is now posted to http://www.thingyverse


Friday October 9th

I made a first attempt at a 3D printed hinge (the project er, hinges on this) this week, having drawn the hinge in Autodesk 123D Design and Meshes.

The technicians at Fabrication were really helpful and when I turned up on Wednesday morning they offered to get it printed by the end of the day. I collected it next morning and discovered that a) I need to be more careful in ensuring that the correct version of a drawing is used, b) my design was not strong enough.  Easily corrected, I thought and went to Epicentre to use Rhino.  Not so easy after all, as it is quite a big learning curve for a novice.

So I am trying again at home, with Autodesk, probably starting from scratch as that seems to be quicker.   Should be ready to try again next week…

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