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Rep Rap

Rapid development of parts

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Speedy Builder529/01/2012 18:59:47
2011 forum posts
141 photos
A few issues ago, the editor 'wrote' a long article on what I recall was called Rep Rap which was a system of 'printing' a 3 dimensional solid on a modified printer. The solid made is in some form of resin / plastic.
Did anyone take this further just look at
I may need to make a 'branding iron' for marking wooden products, using a graphic design contained on a computer. I would need to make a pattern, then get this cast in cast iron at a later date.
Any ideas ?
V8Eng29/01/2012 20:09:09
1438 forum posts
28 photos
There was an exhibitor called "impossible creations" demonstrating at the LMEE last weekend.
The website is:
Hope it helps.
Springbok29/01/2012 21:12:44
879 forum posts
34 photos
For one of castings like this try
He will do one off's useing the lost wax system
John Haine29/01/2012 21:17:15
3109 forum posts
162 photos
How hot does it have to be, is cast iron essential? How complex/big is the pattern? A simpler approach might be to engrave it on a CNC mill on mild steel, I'm sure someone would oblige if it's not too large. I assume that if it is to be used to mark wood it is essentially a planar pattern?
Clive Hartland29/01/2012 21:41:04
2569 forum posts
40 photos
I fabricate them in 3mm x 20mm flat steel bar and form the letters and arc weld onto another piece of 3mm x 20mm and then weld a 5mm rod and form a ring handle.
I use these to brand Beehive items as a lot of thefts are taking place.
The letters I make about 30mm tall.
Much easier this way and one I made 20 years ago is still going strong!
Styx30/01/2012 09:37:36
34 forum posts
42 photos
Hi Robert,
I am half way through building a Prusa Mendel 3D printer but it is a good few months away from being completed. If you are prepared to send me a STL file of the part you need making I will see if I could machine it my CNC mill. It would be good practise for me.
Jeff Dayman30/01/2012 13:18:38
1818 forum posts
45 photos
Just FYI there are commercially made branding irons available, with custom cast brass letter pads. A link to one is below. They are about 60 UK pounds in cost. Probably a lot less effort and overall cost, if you count labour, than making one.
Good luck, JD
tractionengine4230/01/2012 16:40:34
375 forum posts
106 photos
Hi Robert
If it's 2 Dimensional then machining the image with cnc should not be a problem. If the image can be drawn in a 2d cad package a dxf file format can be saved which is ideal.
With the right software it's also possble to use images in Jpeg or pdf file format.
If for some reason your requirement is 3 dimensional, then the most convienient approach would be to model the part in a 3d cad package from which can be saved an stl file format.
Clive Hartland30/01/2012 16:47:59
2569 forum posts
40 photos
Bear in mind that a Branding Iron is 'Reversed'
So when applied to brand it is the right way.
Speedy Builder530/01/2012 18:15:51
2011 forum posts
141 photos
Thanks for all the suggestions and indeed offers of help. The job is for my son in Oz who wants to 'brand' surfboards with his own motif. Another novel method that he has now used, was to do a lino cutting, of the motif and company name etc, then taking a plaster imprint, clean up an then cast in aluminium. Apparently it gets hot enough to scorch without melting.
jason udall31/01/2012 20:37:10
2024 forum posts
41 photos
metal clay...specically bronze
Could use reprap etc then "lost wax"
Stub Mandrel01/02/2012 21:23:06
4307 forum posts
291 photos
1 articles
The expanded polystyrene pattern method explained by Mike Cox would have done it too.
Speedy Builder529/03/2013 10:41:10
2011 forum posts
141 photos

Anyone see BBC One Show 27/03/13 where they demonstrated RepRap ?

Bazyle29/03/2013 14:02:14
5247 forum posts
201 photos

My initial investigation of RepRap is that it is an open source example of hobbyist/school oriented 3D printers which are also produced in various small commercial forms. They have some craft /hobby educational uses but are not in the same league as industrial machines.

The aim of RR is to be easily made by non engineers without machining facilities or knowledge - ie it uses techniques more like model railway, model boats etc. I suggest a model engineer with CNC could well just make the printer head part to try it out on their CNC mill, then design and make a more 'engineered' printer head. If making a whole makerbot a model engineer would have the understanding to perhaps make a more substantial table in the style of a wood router rather than going the more expensive full cnc mill route.

Michael Cox 129/03/2013 14:39:58
532 forum posts
27 photos

It is interesting that Stub Mandrel has raised the possibility of using a lost foam casting process. I presume he was thinking of carving the pattern in polystyrene in some way and then using this pattern for casting.

I have recently been investigating an alternative way of making a pattern in polystyrene that could subsequently be cast. This process is only in the development stage at the moment but it works like this:

A slab of fine grained polystyrene foam (Styrofoam) is taken and the required text is stencilled onto it using a black felt tip marker. The Styrofoam is pale blue in colour and the lettering black. If the styrofoam is exposed to an infrared heat source such as a halogen lamp then the infra red radiation is absorbed strongly by the black area but not by the blue area. The heat in the black areas causes the foam under it to collapse and you end up with the text showing as grooves in the polystyrene.

In a subsequent step the polystyrene could be buried in sand and a casting made from it.

I already have tested the process with fairly large letters circa 40 mm high and it works very well and I am exploring how small I can make the letters and achieve a good result.

Of course the process is not limited to text but it could also be used for simple shapes and patterns as well.

All this is very developmental at the moment but if when I have explored it some more it looks good and I can produce a good casting then, if there is interest, I could perhaps submit an article to MEW.


Stub Mandrel29/03/2013 18:12:20
4307 forum posts
291 photos
1 articles

Hi Mike,

An interesting idea. You remind me that as boys my brother and I use to make buildings out of polystyrene and hen inflict 'war damage' on them with Airfix glue. I'm sure that's how they did the corrosive blood effects in Alien!

Without prejudicing an article, could you post a picture? I don't have a suitable lamp so I can't try this for myself.


John Alexander Stewart29/03/2013 18:37:27
768 forum posts
51 photos
Posted by Bazyle on 29/03/2013 14:02:14:

... I suggest a model engineer with CNC could well just make the printer head part to try it out on their CNC mill, then design and make a more 'engineered' printer head. ..

It has been done with LinuxCNC, anyway. Probably Mach3, but I don't know.

Plunk on a Wades Geared Extruder, rig up a temperature control for melting the plastic, and off you go.

At least in theory, anyway! Every month or two I think of going down this route, then I sit down with a cold drink and settle my thoughts down. *Why* would I want a 3D printer at home?? Got one at work which I could use on a very limited basis, or there's always Shapeways (*).

Shapeways will do metals, which work much better with model locomotives than (roughly extruded) plastic does. At least one of our club members gets bits of metal from Shapeways.

(*note - Alan Hudson, CTO Shapeways and I (And others) worked on the X3D ISO-standardized protocols, and Alan uses this protocol internally for Shapeways purposes. I have no financial commitment, but have been a colleague Alan since the original Shapeways ideas came along, and quite possibly might have some computer code running @shapeways, as we exchanged open-source code many times "in the old days" (I'm really glad to see Alan and his ideas take off and do well - he's a really nice person and deserves success)

Another JohnS

Michael Cox 129/03/2013 19:32:55
532 forum posts
27 photos

Hi Neil (AKA StubMandrel), I have down loaded some photos to an album entitled "Thermal embossing"

The first photo shows a piece of polystyrene about100 mm wide on which I have written some text. The next two photos show the same piece after shining a 50 watt halogen lamp at it for a few seconds. The polystyrene foam has collapsed under the black ink due to greated absorbsion of heat in the black ink.

I only started playing with this technique this week so at the moment it is very developmental.

I have yeat to try the technique with the lettering inverted i.e. black background with the letters unblackened.

I think the technique has potential for nameplates, plaques etc.


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