Video of CNC machining a double sided part.

[Shinobiwan]

It definitely was interesting to see how you get a smooth finish to something you want made, i.e. roughing out first then going over to get rid of those stepped cuts. I have a couple of questions, hope you don't mind,

Yep same here. I always enjoy seeing how others tackled a job and it often gives me idea's. Utube has hundreds of cnc video's luckily.

how long did the whole job take, and did you watch the whole thing? lol

Too right I watched the whole thing! I'm still new at this so was shitting myself! Me and the machine don't quite have the level of trust where I'd walk off and go play some PS3 whilst it cut but we're working on it lol

Rear side took the longest and that's simply because that was the side I did first and bumped into all the problems there. By the time I'd flipped it over onto the front I'd got it figured out and things went like clockwork.


So for the rear side it was an entire day but only a couple of those hours were spent cutting. The rest was head scratching and making changes. The front side was 6 hours from start to finish including tool changes and pausing the machine occasionally to vacuum the chips.


If I did it again I think I could have it done within 8 hours quite easily, probably less because I was on the conservative side with speeds. I'll be doing some more two sided parts in the future such as wave guides but I want to make a permanent jig setup for those as its something I need to be able to do over and over rather than just a one off like these.

when you were roughing out the main shape why weren't you using the extraction, looks like there would be lots of recutting material?

To be honest I wanted to see what the cutter was doing since its the first time I've tried anything this complex. When its buried in a dust hood you don't see things going wrong! There was recutting going off but its only modelling board albeit the high density variety. Still its easy to cut although highly abrasive on cutters - think worse than MDF.

How did your numatic extractor cope when you was using it? I'm thinking of buying a similar type of HPLV extractor and wondering how the the container size coped with the volume of chips. Also what's their duty cycle like? Could you leave it on for a few hours?

Thanks Adil

The 35ltr drum fills up very quickly during a job like this. I think I emptied it 3 times and it does get tiresome however easy the numatic made it to do just that. If you can definitely go with a larger capacity. I'm going to be using an extra bin before the extractor that will add a couple of hundred litres.

It depends when talking about suitability and is up to the task. My model isn't quite up to the job when your cutting fast, the spindle makes more chips than the extractor can collect. If you slow the feedrate down for a short time it gives it time to catch up. I think really you want HVLP type for CNC's because the sheer volume of chips and dust, you need to be moving lots of air. Problem I had is I wanted a one size fits all sort of thing including power tool use so it had to be what I've got now. If I had more room I'd certainly have an HVLP just for the cnc since these are ideal.

I'm pretty sure the duty cycle is continuous on this one. I've had it running for hours. As a bonus it does kick out a fair bit of heat which is great this time of year!

[Iwant1]

since its the first time I've tried anything this complex. !

Well you've done good, the machined outcome looks wicked.

Thanks for the extractor advice, Unfortunately I just bought a wv2, 2000w 90l extractor similar to yours. Made by Yorkleen LTD, but from my research they used to make for Axminister, and still do make for Record, and a few educational machinery suppliers. My thinking was similar to yours, it should be able provide extraction for a host of tools, and again similar to you, I plan to install a ducting system with blast gates everywhere.

Seems like I might have to get a HVLP system just for the CNC, just like I'm looking for a continuously rated compressor for this purpose.

Are these parts, going to be used as the actual speaker fronts that will need prep work and finishing, or are they for the moulds you were planning on making?

Thanks.

[Washout]

That is superb work and I love your speaker designs.

It has me inspired to make some enclosures for my new HTPC setup, although completing my CNC router is unfortunately at the end of a long dependency chain since I moved house at the back end of last year.

Cheers


Chris

[Shinobiwan]

Are these parts, going to be used as the actual speaker fronts that will need prep work and finishing, or are they for the moulds you were planning on making?

Thanks.

Hi again mate,

These are for moulds. Plan is to use polyurethane rubber with the masters used as the plugs, pour that in around them. Let it set and remove then afterwards its ready for casting. This way I can use high density resins with fillers to create my own solid surface/corian like material. Perfect for this application where you want to be getting rid of as much of the vibration as possible.

[kingcreaky]

makes my clock gears look sh1te

outstanding work sir. top of the class

Ive absorbed all your pointers though regarding cutters etc. and just placed an order for some two flute carbide cutters. I also need to think about extraction as combined with fag ash i doubt the mdf is doing my lungs any favours.

also, you come across as a very tidy worker. your workshop looks like an operating theatre and this shows in the quality of your work.

you mentioned modelling board? what is this? As im also still learning im keen to try as many different materials as I can.
I spent £50 on saturday on what is supposed to be Far Eastern Marine ply. but it splinters and frays I think ive just got a bad batch from a bad supplier. But like the look of this material...

[Shinobiwan]

you mentioned modelling board? what is this? As im also still learning im keen to try as many different materials as I can.

Thanks!

This is the stuff:

Polyurethane (PU) 580 Model Board Tooling Block in High Density - Easy Composites

Machines brilliantly although tough on cutters and isn't cheap for what it is. If you need a material that'll give you a super fine finish when sanded, this gives you that.

[Tenson]

So how did you align it to do both sides?

I usually but the piece against a fixed bar to get it in line on one axis and then jog the cutter to a hole on the piece in a known place to align the other axis.

I'm off to make a waveguide today!

[Shinobiwan]

So how did you align it to do both sides?

I usually but the piece against a fixed bar to get it in line on one axis and then jog the cutter to a hole on the piece in a known place to align the other axis.

I'm off to make a waveguide today!

The method your using isn't accurate enough. Not for a two sided part because any error is going to be multiplied by a factor of 2 when flipping it over

Two reference edges cut in a surfaced jig to align the stock parallel to the X and Y and make sure its flat. Then 4 dowel holes were drilled through the jig, table and stock. Took awhile to figure out but its very simple and effective. All datums were at home switch position because the part couldn't move or misalign thanks to the dowels. That meant no probing needed and one less potential error that could creep in.

[Fivetide]

Nice work mate , what you selling those monkey coffins for I would be very interested :) ?

[Iwant1]

I was wondering where Jazz had got to. Hadn't seen any recent activity from him, anyway hope you get better soon.

Two reference edges cut in a surfaced jig to align the stock parallel to the X and Y and make sure its flat. Then 4 dowel holes were drilled through the jig, table and stock. Took awhile to figure out but its very simple and effective.

Ant, if you don't mind and when you got time, I'd appreciate it if you could make a short video of the above method. I just can't get it round my head. Doesn't have to be another £300 speaker mould, lol, just a piece of scrap for visualisation.

Cheers Adil