DW660 Questions

PLHS54
Posts: 60
Joined: Sun Apr 22, 2012 7:36 pm

DW660 Questions

Post by PLHS54 » Tue Jul 31, 2012 7:30 pm

This question is a bit out there, but does anybody have a picture of what the inside of the DW660 looks like? Secondly, does anybody know the diameters of the bearings that are used inside the tool and the distance that the two bearings are separated?

I ask because I'm working on, what I think, is a very viable spindle option for the shapeOko. One that adds rigidity to the z-axis, increases cutting area, lengthens the travel of the z-axis, and stiffens up the whole structure. I just need those three questions answered above and I can finalize my drawings. I would gather this data on my own, but I don't have a DW660 yet. I'll also be posting these drawings, cad files, and renderings for you guys to ponder.

So, if any of you can answer those questions, I'd greatly appreciate it.

Here is a very rough concept I threw together in 5 minutes. It's missing a lot of the hardware and is only loosely dimensioned, but you get the general idea...I hope.
Attachments
Spindle Concept.jpg
Spindle Concept.jpg (62.63 KiB) Viewed 3693 times

zimmer62
Posts: 81
Joined: Fri Jun 22, 2012 4:51 pm
Location: Lansing, MI

Re: DW660 Questions

Post by zimmer62 » Thu Aug 02, 2012 3:38 pm

I was thinking of something sort of like this. Having both sides of the DW660 supported. I think I'd design a bracket that just holds the router in place between then center of two makerslides for the y, I hadn't thought of doubling up on the z-axis slides though.

PLHS54
Posts: 60
Joined: Sun Apr 22, 2012 7:36 pm

Re: DW660 Questions

Post by PLHS54 » Thu Aug 02, 2012 4:13 pm

Although you can't see it in the rendering, my plan calls for taking apart the dw660 and only using the armature. I'm going to mill two plates that the bearings then fit into. These plates then slide up into the square center piece and the square center piece has v-rails on the edges. The advantages of doing it this way is that you have increased travel in the y direction because you don't have two makerslide pieces that are attached to the dw660. Once I can get some finalized dimensions I'll put up a complete rendering.

northbear
Posts: 256
Joined: Mon Apr 09, 2012 9:21 pm

Re: DW660 Questions

Post by northbear » Thu Aug 02, 2012 4:45 pm

Searching lead me to an exploded view. Take a look:

http://www.ereplacementparts.com/dewalt ... _2651.html

or a pdf

http://www.ereplacementparts.com/images ... TYPE_1.pdf


I like your concept! The only problem I can see with it is changing the spindle out (if you want to draw with a pen for example) may be a pain. Also what is your planned access for bit changes?
My buildlog is here

zimmer62
Posts: 81
Joined: Fri Jun 22, 2012 4:51 pm
Location: Lansing, MI

Re: DW660 Questions

Post by zimmer62 » Thu Aug 02, 2012 5:44 pm

I don't think I'll actually be doing this mod any time soon, but I was thinking of having a second gantry, this one wouldn't be under power and would move freely. I've got lots of extra makerslide so the length wouldn't be an issue. I'd see the front most gantry existing just to support the weight and rigidity of the tool... and have it easily removable so it would be out of the way really easy. That would make tool changes okay. I highly doubt I'll ever switch back to putting a pen on the shapeoko though.

Make sure you vent the DW660 if you take it a apart and build a new housing. That motor will generate quite a bit of heat, it has it's own cooling fan built in.

I'd really like to leave my tool in one piece and just figure out a way to stiffen up the z axis.

Digitalmagic
Posts: 123
Joined: Sat Jun 23, 2012 8:47 am

Re: DW660 Questions

Post by Digitalmagic » Thu Aug 02, 2012 8:07 pm

You spawned this Z axis topic thread just when I wonder the actual deformation at the bottom of Z axis.

Based on:
- Real dimensions (X 375mm beam & Z 200mm beam),
- Using 6061 alu as material
- Having Z axis quite low (bit is some millimeters above wasteboard), I simulate a 10lbs force pushing the extremity.
- Single Pulley/Belt on Y-axis, considering one free Y-axis extremity.

I get a 0,59mm displacement at the Z axis extremity, with bonded beams, so including V-Wheels/Rails between X-axis and Z-axis would have probably induced more flexibility.

Okay, 10lbs (bit against material to carve) is probably an exaggerated situation and Makerslide is a bit harder, but this shows that it is a good idea to strengthen the Z-axis in some cases!
Z-axis-Bending.JPG
Z-axis-Bending.JPG (56.86 KiB) Viewed 3621 times
s/o #650 - Wish my digits are ... magic!

PLHS54
Posts: 60
Joined: Sun Apr 22, 2012 7:36 pm

Re: DW660 Questions

Post by PLHS54 » Thu Aug 02, 2012 8:47 pm

northbear wrote:Searching lead me to an exploded view. Take a look:

http://www.ereplacementparts.com/dewalt ... _2651.html

or a pdf

http://www.ereplacementparts.com/images ... TYPE_1.pdf


I like your concept! The only problem I can see with it is changing the spindle out (if you want to draw with a pen for example) may be a pain. Also what is your planned access for bit changes?
Yeah, I stumbled upon many exploded views, just nothing with dimensions. As far as bit changing or mounting any other tool, it's quite simple. There are two ways, first you can leave everything in place and just slide the gantry up to the front of the cnc where you can access the collet nut (this is for an open-ended machine such as the ones with Edwards new mounting brackets.) The second option, although not shown very well in the drawing, allows you to slide the spindle assembly up through the z-axis tube. The second way also allows you to slide in different types of fixtures as well, such as an extruder (I've got that designed too), a laser, or even your pen. These different fixtures are all contained in their own modules, so switching between one another should only take about 10 seconds.

PLHS54
Posts: 60
Joined: Sun Apr 22, 2012 7:36 pm

Re: DW660 Questions

Post by PLHS54 » Thu Aug 02, 2012 8:53 pm

zimmer62 wrote:I...Make sure you vent the DW660 if you take it a apart and build a new housing. That motor will generate quite a bit of heat, it has it's own cooling fan built in.

I'd really like to leave my tool in one piece and just figure out a way to stiffen up the z axis.
Yes I will be venting the housing, as well as running a fluid delivery line through the body to supply cutting fluid to the endmill and workpiece when machining metals. Although, I assume the fluid running through the body won't do much in the way of cooling the motor down, I still think it's a neat feature.

Also included in the housing is vacuum tube, so all you have to do is attach your shop vac up to the top of the z-axis (this isn't shown in the rendering)

I'll send you a design I came up with to stiffen up the z-axis while keeping the tool in one piece. I may start a thread on that too. I think it's quite good actually! The only reason why I'm not going that route is because I wanted a smaller overall axis and I wanted to add many different configurations.

PLHS54
Posts: 60
Joined: Sun Apr 22, 2012 7:36 pm

Re: DW660 Questions

Post by PLHS54 » Thu Aug 02, 2012 8:57 pm

Digitalmagic wrote:You spawned this Z axis topic thread just when I wonder the actual deformation at the bottom of Z axis.

Based on:
- Real dimensions (X 375mm beam & Z 200mm beam),
- Using 6061 alu as material
- Having Z axis quite low (bit is some millimeters above wasteboard), I simulate a 10lbs force pushing the extremity.
- Single Pulley/Belt on Y-axis, considering one free Y-axis extremity.

I get a 0,59mm displacement at the Z axis extremity, with bonded beams, so including V-Wheels/Rails between X-axis and Z-axis would have probably induced more flexibility.

Okay, 10lbs (bit against material to carve) is probably an exaggerated situation and Makerslide is a bit harder, but this shows that it is a good idea to strengthen the Z-axis in some cases!
Z-axis-Bending.JPG
Very nice FEA, I'm also putting together different simulations on my design to see how it reacts, well done. Does anybody know more accurately the magnitude of the forces encountered when milling, or is 10lbs a good estimate?

Also, something else to consider is impulse, such as when your bit suddenly catches on something. This creates a big force quickly, although this force isn't something encountered regularly, it's enough to wreck the piece you're working on. So strengthening your z-axis is a good idea.

Digitalmagic
Posts: 123
Joined: Sat Jun 23, 2012 8:47 am

Re: DW660 Questions

Post by Digitalmagic » Thu Aug 02, 2012 9:29 pm

Simulating the frictional drill-bit is not easy, you have to integrate the material abrasion.
Many papers like this discuss this topic: http://soar.wichita.edu/dspace/bitstrea ... t06079.pdf

Stress analysis underlines the Makerslide structural reaction, and can help for scaling up Shapeoko, using double beam, or 40x40 rails;
About the bit driven force, I would experiment with the parameters (bit model, RPM, material to carve, depth, rates, ...) to reduce it at best, or with an accuracy goal.
s/o #650 - Wish my digits are ... magic!

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