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Multi-Way Conventional loudspeakers with crossovers

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Old 6th March 2013, 01:29 PM   #571
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Quote:
Originally Posted by Tigerpolis View Post
Very interesting! Im thinking of doing the same on my next speaker project! Where do you plan to get all the moulding material? And also the aluminium trihydroxide, im having a really hard time finding it! The only site that sells it dosen't seem to have it in stock.. I think i will order this kit: Silicone Mould Resin Casting Starter Kit with Fast Cast Polyurethane Resin - Easy Composites
To start experimenting a little bit! What do you think about maybe putting a layer of gelcoat before the resin to get a high gloss surface?

/Sebastian
I've used these so far and have been happy with the service from each. Easy composites are particularly good. Gave them a call, explained what I wanted to do and they gave lots of helpful advice.

Carbon Fibre Cloth, Epoxy Resin, Kevlar, Diolen, Equipment and Supplies for Advanced Composites - Easy Composites

Mould Making and Casting Supplies from Bentley Advanced Materials

TOMPS : Mould Making Supplies : Casting Supplies : Plasterers Supplies

For the gel coat I'm not bothering as the cast will be sprayed anyway but if your looking for the best finish straight out the mould then that would give a high gloss and hard durable surface.

Aluminium Trihydroxide is also known as Trihydrate or ATH. Some info here:

Aluminium Trihydrate - Alumina Hydrate, Aluminium Hydroxide, Aluminium Trihydroxide from aluminahydrate.com

Try using those to widen your search but I know these sell it and had it in stock a month or so ago:

ATH - ALUMINIUM TRIHYDRATE
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Old 7th March 2013, 10:20 PM   #572
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Not normally worth posting about replacing the bed but I picked up a sheet of Trespa Athlon from a friend and have to say this is makes a great bed. Plenty of mass(about twice as heavy as MDF on a like for like basis), well damped against vibration, dimensionally stable, tough and still easy to drill and set up fixtures. The construction is a fibre reinforced resin with a laminated finish. I've had a quick go with an offcut made when sizing the sheet to fit the bed and it machines really nicely.

Aside from making a good bed all this has got me thinking it'd be ideal for speaker construction. I got this sheet for nothing and I'm not sure on pricing but I'll find out.

Click the image to open in full size.

Click the image to open in full size.

My modelling board arrived today. Weighs a ton! The masters for the baffles will be coming out of this soon.

Click the image to open in full size.
Attached Images
File Type: jpg Trespa Athlon Bed 1.jpg (181.5 KB, 1250 views)
File Type: jpg Trespa Athlon Bed 2.jpg (186.9 KB, 1248 views)
File Type: jpg Sika Block.jpg (123.9 KB, 716 views)
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Old 7th March 2013, 11:12 PM   #573
ORNJ is offline ORNJ  United States
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If only I had your resources!

Man, you do great work and have some great tools!

Bravo!
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Old 8th March 2013, 09:46 AM   #574
sploo is offline sploo  United Kingdom
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Quote:
Originally Posted by ShinOBIWAN View Post
My modelling board arrived today. Weighs a ton! The masters for the baffles will be coming out of this soon.
If that modelling board is the same material I got hold of (offcuts from a CNC company near where I used to work) you'll love machining it. It cuts like butter, creates chips not dust, and you get incredibly sharp, clean edges that require little or no finishing. It will dent, so needs handling with a bit of care, but is great for prototypes and mold making.
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Old 11th March 2013, 01:17 AM   #575
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This was a cool challenge not least because there was over 300 worth of stock material at risk if I nobbed it up!

A couple of days worth of planning, many iterations of tool paths and simulations and a day spent building and testing the double sided jig. This made a really nice change of pace from the usually slap a sheet of 4x4ft on the bed and press go. I've only had practical hands on experience with the cnc for the past few weeks and only done a handful of jobs so at time I thought I'd bitten off more than I could chew with this but it came good in the end. The two sides lined up virtually perfect and I couldn't be happier with the results. I learnt a lot from this, not least that long cutters (105mm from the collet) are whole other ball game and first hand experience of the superiority of carbide vs hss when cutting highly abrasive materials as well as the folly of using too many flutes and incorrect chip load. Burned two cutters up because of that just on this one job.

I'll post some of the pics later but for now here's a video:

CNC Cutting Loudspeaker Baffles - YouTube
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Old 11th March 2013, 05:01 AM   #576
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Quote:
Originally Posted by Boden View Post
Hi Shinobiwan,

As much as I admire your work, I would take the separate subs advice to heart.

Impressive as the speakers physically and hardware-wise are, in sub-bass they are -as most integrated high enders- rather fighting the room than melting into it.
Welti and others have shown the way.

Good luck.

Eelco
I so agree with this
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Old 11th March 2013, 10:13 AM   #577
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Quote:
Originally Posted by ShinOBIWAN View Post
This was a cool challenge not least because there was over 300 worth of stock material at risk if I nobbed it up!

A couple of days worth of planning, many iterations of tool paths and simulations and a day spent building and testing the double sided jig. This made a really nice change of pace from the usually slap a sheet of 4x4ft on the bed and press go. I've only had practical hands on experience with the cnc for the past few weeks and only done a handful of jobs so at time I thought I'd bitten off more than I could chew with this but it came good in the end. The two sides lined up virtually perfect and I couldn't be happier with the results. I learnt a lot from this, not least that long cutters (105mm from the collet) are whole other ball game and first hand experience of the superiority of carbide vs hss when cutting highly abrasive materials as well as the folly of using too many flutes and incorrect chip load. Burned two cutters up because of that just on this one job.

I'll post some of the pics later but for now here's a video:

CNC Cutting Loudspeaker Baffles - YouTube
Wow! Will you then pour silicone on that to make the moulds? Thanks for the links btw! I will receive my "kit" tomorrow hopefully, then i will start to experiment with fillers, marble powder and metal powders! I't would be pretty badass to have a brass like baffle!
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Old 11th March 2013, 01:01 PM   #578
sploo is offline sploo  United Kingdom
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Quote:
Originally Posted by ShinOBIWAN View Post
This was a cool challenge not least because there was over 300 worth of stock material at risk if I nobbed it up!

A couple of days worth of planning, many iterations of tool paths and simulations and a day spent building and testing the double sided jig. This made a really nice change of pace from the usually slap a sheet of 4x4ft on the bed and press go. I've only had practical hands on experience with the cnc for the past few weeks and only done a handful of jobs so at time I thought I'd bitten off more than I could chew with this but it came good in the end. The two sides lined up virtually perfect and I couldn't be happier with the results. I learnt a lot from this, not least that long cutters (105mm from the collet) are whole other ball game and first hand experience of the superiority of carbide vs hss when cutting highly abrasive materials as well as the folly of using too many flutes and incorrect chip load. Burned two cutters up because of that just on this one job.

I'll post some of the pics later but for now here's a video:

CNC Cutting Loudspeaker Baffles - YouTube
Ant - superb work. Though there are some movements (e.g. around the 30-40s mark) that look a little slow for the cutting rpm and would risk heat problems.

That 105mm cutter is a monster. I'll bet the deflection problems were interesting.

Like the idea of having a couple of baffles along the length of the machine so the chips are kept on the table, rather than falling onto the rails.

BTW Scare me - how long did that whole job take?
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Old 11th March 2013, 04:13 PM   #579
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Originally Posted by ShinOBIWAN View Post

Its a bunch of clever macro's and a matching screenset for Mach3 and two touch probes - one mobile for setting the initial work piece zero and a fixed plate for measuring tool length between changes. Dead easy to use and I have no issues with changing up to 7 bits in one job. The only inconvenience is have to change your bit but unless you get a megabucks auto changer and mega-mega bucks ATC spindle then this is as good as gets.

Link to the screenset:

The CNC Woodworker - Mach3 2010

Its about 13 but the best money I've spent on the CNC by far.

Here's a nice video that shows how it all works:

Mach3 2010 Screenset Tool Change - YouTube
Hi Shin,

Sorry if it's OT but I just want to ask you the software version of your Mach3, are you using 3.43.66? or 3.43.62?
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Old 11th March 2013, 07:28 PM   #580
ScottG is offline ScottG  United States
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Quote:
Originally Posted by ShinOBIWAN View Post

I'll post some of the pics later but for now here's a video:

CNC Cutting Loudspeaker Baffles - YouTube
Nice!

'tis a lot of dust though, no?

I still think the better idea is a continuous stream(s) of compressed air at the bit/work area scattering the debris to the edges of the work surface (..with a vacuum pick-up from there). And though speculative, I'd still imagine that compressed air streams would cool the bit (a "bit") and prolong bit-life. (..again, similar to what heavy industry machines use with liquid for metal milling.)
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