Trim Router (eg DW660) - suitability for PCB milling?

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jagmills
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Trim Router (eg DW660) - suitability for PCB milling?

Post by jagmills » Tue Nov 19, 2013 1:42 pm

Hi everyone,

I've been hiding on these forums planning my (first) upcoming build of a Shapeoko (specifically an eShapeoko when the kits get back in stock). First of all I just wanted to say you guys have an awesome community :)

So as my first post I have a question I haven't really been able to figure out.
My plan is to have my Shapeoko setup in my garage, almost as an all-purpose tool - things I want to do with it will be milling wood (guitar making), milling aluminium, plotting, perhaps adding a laser cutter into the mix at some point - and probably the difficult part, I would like to be able to mill my own pcbs as well.

I haven't found anyone who has a machine that has operated on both ends of the spectrum, as it were. I would like my work area to be 1m x 1m, a router that can handle heavier milling tasks, nema 23s (and the suggested eShapeoko upgrades e.g. dual rails, dual y motors etc.). But would this still have the required accuracy to mill a PCB? I'm not after tiny trace spacing, but SMD work may be a consideration in the future.

As I see it problems could be:
- Does a bigger machine result in less accuracy? The PCB mills I have seen are tiny desktop versions
- Would a powerful, bigger router cause issues? My thoughts on that is bigger = more chance for tool eccentricity, less precision, more inertia on the machine

Another option I suppose I have is to have swappable spindles. One for heavy duty stuff, e.g. DW660, and a smaller dremel-type for the pcb work - if the machine size is suitable that is.

So if anyone has tried milling PCBs on a larger machine or have any suggestions/reassurances, I'd be grateful to hear them - I hope my wish of an all-purpose machine is somewhat doable :)

Thanks for your time!
Proud owner of eShapeoko #262 - 1mx1.5m, dual x axis, NEMA 23s for XYZ, ACME TR 8 x 2 leadscrew and deluxe frame. Makita RT0700c.

cvoinescu
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Re: Trim Router (eg DW660) - suitability for PCB milling?

Post by cvoinescu » Tue Nov 19, 2013 2:02 pm

I haven't milled PCBs yet, but I can answer some of your questions.

It's true that a more powerful tool will likely have more runout, but that's not a hard and fast rule. The DW660, for instance, is likely to be better than a smaller Dremel knock-off. For PCBs, the best spindle I can think of is a 300 W DC spindle from China (plenty of them on eBay). It's quiet, acceptable runout, and plenty powerful for PCB work. I think the DW660 with some form of speed control would work fine too.

Swapable spindles: nobody has a good quick-release mechanism yet (or if they do, they're keeping mum). The ideal mechanism should be rigid, cheap to build, easy to use, accurate and repeatable, and it should add as little as possible to the distance between the tool and the X axis. There has been talk in the past of swapping the entire Z axis, too. Maybe now, with the inverted Z axis, someone will come up with a neat design.

The bigger machine has less absolute accuracy over long distances, obviously, but it is also a bit less accurate if you're milling a small object in a corner, compared to a smaller machine. The biggest difference comes from the longer belts, that stretch more for the same force; the heavier gantry and motors also limit the acceleration, and strain the belts more. If you do your PCBs in a corner of the work area, flex from the MakerSlide itself is less of a concern. Still, you should be able to get acceptable precision for all but the smallest SMD work, if you don't also demand blistering speed.
Proud owner of ShapeOko #709, eShapeOko #0, and of store.amberspyglass.co.uk

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Re: Trim Router (eg DW660) - suitability for PCB milling?

Post by WillAdams » Tue Nov 19, 2013 2:21 pm

cvoinescu wrote:Swapable spindles: nobody has a good quick-release mechanism yet (or if they do, they're keeping mum). The ideal mechanism should be rigid, cheap to build, easy to use, accurate and repeatable, and it should add as little as possible to the distance between the tool and the X axis. There has been talk in the past of swapping the entire Z axis, too. Maybe now, with the inverted Z axis, someone will come up with a neat design.
I've got a design drawn up which takes advantage of the nifty machined aluminum brackets Inventables uses --- not quick release, you have to attach it using four screws, but hopefully fairly repeatable.

William
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets
Nomad 883 Pro #596 (bamboo)

jagmills
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Re: Trim Router (eg DW660) - suitability for PCB milling?

Post by jagmills » Tue Nov 19, 2013 2:43 pm

Hi cvoinescu,

Thanks for the reply - funny to see that you live just down the road from me!

The options that I had in mind so far were the DW660, the apparent popular choice - but also the Makita RT0700CX4 which had variable speed control as well as IMO a nicer metal body, or the recently posted Cau Cau http://www.shapeoko.com/forum/viewtopic.php?f=8&t=2037 seemed like an interesting choice.

I did see the 300W DC spindle, but as the general purpose machine idea I had in mind it seemed that this may not have enough grunt to do some of the more taxing tasks I had in mind. However it does seem to be something you'd get a feel for - and I imagine once I get the hardware setup and plotting with a pen, then I'll get a better feel for it.

I agree, a quick-release mechanism would be ideal for the situations I'm imagining myself to be in. I do at least aim to try and come up with something along those lines once I get into the swing of using it. Official promise, if I do design something I won't kept it a secret.

I'm not aiming for blistering speed in milling PCBs at all - but it's good to know there are tricks to increase my accuracy. Etching PCBs at home is something I've only done a handful of times, and it really is a lot of work. It seems milling is quite a nice alternative, and producing a milled and tinned PCB would take no time at all.

I suppose if I did need more accuracy I could always build another Shapeoko :)

Thanks again!
Proud owner of eShapeoko #262 - 1mx1.5m, dual x axis, NEMA 23s for XYZ, ACME TR 8 x 2 leadscrew and deluxe frame. Makita RT0700c.

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Re: Trim Router (eg DW660) - suitability for PCB milling?

Post by cvoinescu » Tue Nov 19, 2013 11:19 pm

jagmills wrote:Thanks for the reply - funny to see that you live just down the road from me!
Old Dean, so even closer than you may have thought! :)

The DW660 is not easily available in Europe, and comes only in an 120 V version (but it works fine with a 110 V construction site transformer).

The Makita RT0700C is a lovely spindle indeed. The European equivalent of the Bosch Colt, the GKF600, is also great, and lighter than the Makita, but it doesn't have speed control. I don't care, I can build one with parts that I already have. Screwfix have it on sale for £99.99 (I just bought one).

You are entirely right about the Chinese 300 W DC spindle, of course. It's not enough as a general-purpose spindle, but I got one to try it for PCBs and other small jobs. Haven't had a chance yet...
Proud owner of ShapeOko #709, eShapeOko #0, and of store.amberspyglass.co.uk

jagmills
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Re: Trim Router (eg DW660) - suitability for PCB milling?

Post by jagmills » Wed Nov 20, 2013 8:40 pm

Haha, old Dean! Even closer indeed. Small world :)
cvoinescu wrote:The Makita RT0700C is a lovely spindle indeed. The European equivalent of the Bosch Colt, the GKF600, is also great, and lighter than the Makita, but it doesn't have speed control. I don't care, I can build one with parts that I already have. Screwfix have it on sale for £99.99 (I just bought one).
I have been leaning towards the Makita for a little while now. I saw the GFK600 was on sale too, but have found a couple of places that do in fact sell the Makita for about £95. I do like the idea of the variable speed, for me that is a nice feature (plus owning a decent trim router would also benefit my tiny garage workshop).
Speaking of the Makita...
cvoinescu wrote: Swapable spindles: nobody has a good quick-release mechanism yet (or if they do, they're keeping mum). The ideal mechanism should be rigid, cheap to build, easy to use, accurate and repeatable, and it should add as little as possible to the distance between the tool and the X axis. There has been talk in the past of swapping the entire Z axis, too. Maybe now, with the inverted Z axis, someone will come up with a neat design.
One thing I do very much like about it is the solid metal body and the various bases you can fit it into. That got me thinking - the standard base for the Makita has this quite wonderful quick clamp/depth adjustment mechanism (youtube link: http://www.youtube.com/watch?v=TAYMsLCMn8k shows it within the first minute). Now, I'm sure you can see what I'm thinking with this - mounting the base directly on to the Z axis would allow you to whip the router out with no trouble. I imagine the spindle distance from the X axis would not be increased by much, but the base might obviously add additional weight.

However my idea would be simple - such a format could easily be replicated, i.e. creating a false router body that clamps around another spindle - perhaps 3d printed. Hey presto, you have a fairly standard shaped spindle that clamps into the router base on your Z axis, with what looks to be a minimum amount of fuss to remove.

I think I will be going with the Makita. I already have a Dremel tool somewhere that I could swap to if I hated the router's performance on PCBs, but I won't know until I try!
Proud owner of eShapeoko #262 - 1mx1.5m, dual x axis, NEMA 23s for XYZ, ACME TR 8 x 2 leadscrew and deluxe frame. Makita RT0700c.

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Re: Trim Router (eg DW660) - suitability for PCB milling?

Post by Improbable Construct » Wed Nov 20, 2013 9:16 pm

one thing to remember is that every time you remove and replace a spindle you have to tram it.
That is to get it perfectly perpendicular to your work surface. Other wise you will get cuts that do not lign up on multiple passes.
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Re: Trim Router (eg DW660) - suitability for PCB milling?

Post by cvoinescu » Wed Nov 20, 2013 9:23 pm

Any quick-release worth its salt would preserve the alignment. Otherwise, there's nothing quick about it -- ok, the release would be quick, but I'm looking for the re-attachment to be quick too. :)
Proud owner of ShapeOko #709, eShapeOko #0, and of store.amberspyglass.co.uk

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Re: Trim Router (eg DW660) - suitability for PCB milling?

Post by northbear » Thu Nov 21, 2013 4:57 pm

Improbable Construct wrote:one thing to remember is that every time you remove and replace a spindle you have to tram it.
That is to get it perfectly perpendicular to your work surface. Other wise you will get cuts that do not lign up on multiple passes.
My "quick change" is to have a separate piece of z axis makerslide for each type of "spindle" and then remove the two bolts attaching the z axis motor to the z axis makerslide to change between spindles. (see pix below bolts circled in red for an example - not actually my machine).

Steps to do this would be
1) remove bolts
2) un-thread z axis threaded rod from z axis nut
3) remove old spindle from machine (mounted on makerslide)
4) drop in new spindle into machine (mounted on makerslide)
5) thread z axis into z axis nut
6) reattach attach bolts to new spindle

It doesn't take more then a few minutes and I don't need to do anything but re-home the machine. My thought is once I get the router (or other "spindle") mounted square and plumb to the makerslide I can swap it in and out and keep the tramming correct

Of course this would be more work with your ACME screw upgrade as there would be more to disassemble.

Image

Note: This post is basically a copy of my post from when I was in the planning stages. http://www.shapeoko.com/forum/viewtopic ... 716#p12894
My buildlog is here

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Re: Trim Router (eg DW660) - suitability for PCB milling?

Post by cvoinescu » Sat Nov 23, 2013 1:24 am

Having seen both the Makita RT0700C and the Bosch GFK600, I think I like the Makita a little more. It's heavier and a little louder, granted, but the barrel is made entirely of aluminum, and it simply looks better made. Both have a router base that clamps with the same type of mechanism. The height adjustment is a nice rack-and-pinion on the Makita. On the Bosch, it's a thumbwheel with M6 thread that engages grooves on the body -- it feels looser and less precise. It doesn't matter, though, because you would not use either base, except if you modify it to turn it into a spindle mount.

Another difference is that the UK version of the Bosch GFK600 comes with a 1/4" collet, and no other collet sizes exist for it, while the continental European version comes with 6 mm and 8 mm collets. The 1/4" collet is not compatible with the European model (different collet size, different cone angle, different nut). A 1/4" collet does not exist for it.

The UK version of the RT0700C comes with 1/4" and 3/8" collets, and the European version again with 6 mm and 8 mm collets, but, as far as I know, they are all interchangeable (using the same nut).

1/8" collets do not exist for either spindle.

I have not had the opportunity to test the Makita (I had not bought it for myself), but the Bosch is mine and I'm going to use it soon.
Proud owner of ShapeOko #709, eShapeOko #0, and of store.amberspyglass.co.uk

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