Looking for help with a project

si_vis_pacem

Hi,

I don't think I could afford a monthly membership on a regular basis, but there is a particular project I'd like to do and I'd be willing to sign up for a month to get it done if that's in any way possible.

Basicly I'm trying to take a 3D model and make it into a brass/bronze object (ideally around 5 or 6 copies). It's a cap badge around 3cm across 2cm high and 0.5cm deep. So far I've considered the following:

Get a professional brass caster to do it: Hard to find/too expensive/they usually only do larger pieces.

Order a brass/bronze plated steel copy from shapeways: I cannot overstate how expensive this worked out as XD

Order a plastic copy from shapeways, make a lost wax mould, cast in pewter, electroplate with brass: Less expensive, but still not exactly cheap enough to make it doable.

Then I came across your website and it occurred to me that you guys not only seem to have all the equipment, but you seem to have actually done stuff like this before. So instead of giving my money to some company in the US or Germany I could give it to a local group, get my hands dirty, and possibly actually get it done on budget.

In return for any help I'd be willing to, contribute money to the space, pay for any materials (obviously), possibly contribute 3D modelling help for future projects using 3DS Max or Blender (if you need it).

Thanks

zg3409

It would be best if you joined the public mailing list for TOG and discussed your project there. Then those with most interest/experience in your project could assist you.

We have a CNC router, which may be of use, and a somewhat unreliable 3D printer. The CNC router can cut metal, but it depends on the shape etc.

Regarding joining, there is no need to. If you did pay for a month, you would still not get a set of keys, so you would still be reliant on other members to be in the space to open up and close up for you. We are not pushing people to join, however if you pay a minimum of 20 Euro a month, you could eventually get a set of keys and come and go as you please 24/7. However you would need to visit the space somewhat regularly before we hand out a set of keys to a stranger.

There is information on the CNC router on a hidden webpage (wiki), and there are at least two people who have used it in the past. At least one guy has done some moulding in the past, but not with metal.

You would need training to use the CNC router and there are safety and there are risks of damaging it. Ideally use it only with help.

TOG should be open all this Saturday (see the calendar on the website), but it would be best to post your project to the public mailing list with as many details as possible.


Here is instructions how to join
http://www.tog.ie/2012/03/mailing-lists/

https://lists.tog.ie/mailman/listinfo/tog


Below is a quick summary of the CNC:

About It's a Conect Contour Minor CNC milling machine. It can handle work of up to 165mm x 100mm x <height> (more if you are cunning and careful). Good for drilling holes in accurate patterns, engraving patterns and cutting out shapes.

Conect Contour MinorTODO: what's the maxiumum height?

TODO: what's the resolution?

Safety The machine will stop if you open the door. (Unless you have activated the guard override with the key. This is not recommended.)
The machine will stop if you hit the emergency stop button. However, this is also likely to damage your work and the bit. Only do this in a genuine emergency.
When working on oversized projects, the machine may drive the work into the sides, causing damage.
The bits are really sharp. It's recommended to take out the bit (or the whole chuck) before working underneath it.
How to use it

2) Run 2D Design Fire up the computer and run 2D Design. This software allows you to create a design, and then controls the mill to produce it.

3) Set Profile Go to the Setup -> Plotting Device menu and select the Conect Contour Minor profile.

4) Develop your model.2D Design has tools similar to most CAD/Paint packages (lines, circles, text etc.) and uses colours to represent different bits and depths.

More info on 2D Design.

5) Secure the work piece. To protect the machine, first put a piece of scrap wood on the table, then your work on top. To secure your work:

Securing the work to the table1.As a precaution, remove the bit from the chuck (see below)
2.Use the spanner to undo the vice as far out (right) as it will go by turning the bolt on the right hand side of the block.
3.Use the large allen key to undo the whole block.
4.Place the scrap wood, then your work on top.
5.Move the block up against your work and tighten it down again.
6.Use the spanner to tighten the vice to secure your work.
The work must be held securely, but take care not to bend it or the milling will not be of a consistent depth. Make sure it's level relative to the table.

6) Install the (first) bit Bits, chucks, allen keys etc. are stored in the 'Illy' tin in/near the mill.

Tin of bits, etc.Before opening the tin, pause to admire the milled lid and note the effects of milling a concave surface. There are calipers somewhere in the workshop if you need to check the diameter of a bit.

Removing the chuck
A chuck with a bit installed
To change the bit:
1.Remove the bit from the chuck, using small allen keys.
2.Remove the chuck, by squeezing the brass blob, turning the black ring left and the chuck to the right, and pulling.
3.Insert the bit and tighten small allen bolts.
4.Align the tabs and clip the chuck into place.
Switch the machine on.

7) Select File -> Plot.
Hit Pens/Tools. This dialog is where you set the meaning of each colour.

Hit 'Add draw colours' to list all the colours used in your model. For each colour, set up:

order
tool (i.e. which bit to use, if you need more than one)
final depth
clearance (how far to move the bit up before moving it across. Make it higher than any protrusions in your work. If your work is flat, a few millimetres is fine.)
Tools can have

diameter (of the business end of the bit)
depth per pass (harder materials need a shallower depth per pass, and therefore more passes)
offset (not sure how this works but it controls for bits of different lengths. Possibly.)
When everything is specified, hit Ok. The mill will start spinning and move up, and the table will zero itself.

8) Set the datum point Wait for the 'Determine the material datum...' dialog to appear.

Then press Read Material Datum. Wait for the next dialog:

Then use the red manual control buttons on the front of the machine to move the bit to the back right corner of your work.

Move bit to back right cornerUse a bit of scrap paper between the bit and your work to avoid damage, then remove the paper and press Ok. Note: THE DIAGRAM IS A LIE, on this machine the 'start position' (0,0,0) is the near top left point, not the near top right point.

Finally, fill in the X and Y: X=165.00, Y=98.00. Leave Z at whatever it is. Once set, you only have to redo this if you move or change the work.

9) Start milling Press Ok. The mill will move back to the top back right position, then a dialog will appear asking you to install the bit for the first colour. Change the bit if required, then press Continue.


10) Keep an eye on it Be ready to stop the machine (e.g. by opening the door a tiny crack) if it is about to crash, or it seems unhappy. The spindle load (gauge on the front of the machine) should not go above 5. Spindle load is highest during diagonal movements.

Miscellaneous weird stuff is happening.
Sometimes the software forgets the profile of the mill. Restart the software and reselect the mill from the Setup -> Plotting Device menu.
Why can't I use Google Sketchup to create the model?
We only have Sketchup, not Sketchup Pro, which doesn't export DFX files (and Sketchup can't drive the mill itself).
Why can't I use 2D Design v2?
v2 might be better for drawing but it doesn't have a profile for the Conect Contour Minor. (Maybe this can be fixed...)
I tried to mill something and the mill is screaming.
You are going too fast, or using the wrong bit for the material. Try a much lower speed and a smaller depth per pass.
I started milling but I want to abandon it.

DON'T PRESS EMERGENCY STOP or switch the machine off (this will drop the bit through your work and probably damage it). Hit Escape and the software will stop the milling process, leaving the mill stationary but still spinning. Then open the door a tiny crack (if you feel safe doing so) and the mill will stop. (There must be a better way to do this, but what is it?)
The accuracy of the X axis is poor.
The X axis lead screw / bearings need replacing.
I tried to mill but I got a warning that the cutting head did not move to the point required.
Check that the correct profile is set (other machines have different specifications). Redo the datum point calibration.
I can't get the chuck back in.
The black ring has been left in the 'closed' position. Press the brass blob in and rotate the black ring to the left relative to the silver column. The black ring will lock into the 'open' position and allow the chuck to be inserted.

Parts Bits can be purchased on eBay. We have two chucks which accept bits of 6mm and 10mm diameter shank respectively. Namit is considering making an adapter so the chucks will also take imperial bits. Bits have different properties: they are intended for different materials and also for either drilling downwards or milling across the material (or both, at greater expense). The smallest bit we have at present is 3mm diameter.

Results Projects using the mill: ... nothing much yet (mostly wooden formers)

Materials milled:

Wood
Aluminium
Slate
Polycarbonate (bouncy and tough to mill)

si_vis_pacem

Hi, thanks for all the information. I think the best thing might be to drop along on Saturday and have a chat with someone. There's two events timetabled, electronics bootcamp and open social. Which would you recommend?

And I wasn't expecting to get a key or anything. This isn't a massive project so I'll probably only need a few hours in total.

zg3409

It is usually a good idea to try arrive a couple of hours before the social (say 5pm) but also important to let those who have used the CNC etc know you will be there so they can discuss it with you.

The place normally gets busy after 8pm and it can be hard to talk to people about projects. I am away this weekend, so I won't be around.

mccalld

I happened across this by accident looking or a course on CNC milling preferably with 5 axes but 3 would be fine to start.
I seems the group has a CNC milling machine which I would be interested in learning how to progamme and use. if membership were open.
I have an electrical engineering background and an interest in wood carving. In reply to the person looking to make cap badges. Making a silcon mould for the badge is relatively easy and could be used to cast pewter or wax to use in lost wax casting. Tools need Lego to mage mould container. Marla (plastecine) to embed one side of the piece while puring one sied of the mould. red 2 part silicone available from Alec tiranti and pewter and pouring ladel. and talc for mould. I have done it making replica toy soldiers etc many times.

zg3409

If you are interested in using TOGs CNC then this would not be a problem. It has some limitations but these would be apparent quickly.

It would be best to join the public mailing list and ask someone to demonstrate it to you first. We also have documentation on the wiki. You do not need to join to use it. You need to join if you want your own key to come and go as you please.