Need a good table top scrolling CNC!

[RoboChair]

Originally Posted by Frank Neuperger

So Velox seems better on the motor torque and resultant effective stiffness in the drive train. Laguna has more mass and possibly structural stiffness. Why is the Velox repeatabilty claim twice as good.

Because the Velox machine is built with good materials and good design to make it very stiff. Weight does not always = rigidity. The router I have at work I can grab the gantry and get it to visibly oscillate, can't make the Velox budge.

While I do not currently have tests to detail for you I will say that greater than 75% or our robot this year was created on the Velox router. Every single custom gearbox was made with it, the holes are not 100% perfectly round but are unlikely to with any router so we post ream all the bearing holes. Over 20 gearbox plates easy. Any tolerance issues we have had with it have been almost always user error and not the machine. We also made chain sprockets that if they are even off by a thou are terrible at meshing, worked fine every time(something the Haas vertical mill I have at work hasn't lived up to even).

As a side note, while I was picking ours up at their shop they told me that some clients had even managed to pull off machining stainless steel. That is nuts that they managed to do that with any router.

[sanddrag]

If you can make sprockets on a router but not on a Haas, something is very wrong with your setup or process on the Haas. I highly doubt it's the machine.

[RoboChair]

Originally Posted by sanddrag

If you can make sprockets on a router but not on a Haas, something is very wrong with your setup or process on the Haas. I highly doubt it's the machine.

I meant to say that the Hass has not had a 100% success rate(works basically every time), not that it can't do it. Part of the issue there is to make a #25 chain sprocket you need to use a 1/8" endmill or smaller and the max spindle speed on the Hass is 7500 rpm when I should be running said endmill at 15000 rpm. So you have to turn the feed down. Also our 1/8" endmill is set in it's tool holder with just over 1" of stickout for clearance reasons with the parts we make and tool deflection doesn't help.

Enough of my rambling.

My point is your results with any machine are driven primarily by 2 factors. First is how well constructed you machine is. Second is how you use it. You can use a lesser machine to make the same part with comparable quality but it will take longer, more work, and have a higher chance of failure while doing so.

If I had to pick between a brand new VMC CNC with all the features and a VeloxCNC Router with all the options and both were free, I would pick the router every single time.

[Aboudy Dairi]

Originally Posted by RoboChair

Because the Velox machine is built with good materials and good design to make it very stiff. Weight does not always = rigidity. The router I have at work I can grab the gantry and get it to visibly oscillate, can't make the Velox budge.

While I do not currently have tests to detail for you I will say that greater than 75% or our robot this year was created on the Velox router. Every single custom gearbox was made with it, the holes are not 100% perfectly round but are unlikely to with any router so we post ream all the bearing holes. Over 20 gearbox plates easy. Any tolerance issues we have had with it have been almost always user error and not the machine. We also made chain sprockets that if they are even off by a thou are terrible at meshing, worked fine every time(something the Haas vertical mill I have at work hasn't lived up to even).

As a side note, while I was picking ours up at their shop they told me that some clients had even managed to pull off machining stainless steel. That is nuts that they managed to do that with any router.

What are your typical cut parameters in aluminum? What size tool, speeds and feeds, width, depth? Im very curious now.

[techhelpbb]

Originally Posted by RoboChair

I meant to say that the Hass has not had a 100% success rate(works basically every time), not that it can't do it. Part of the issue there is to make a #25 chain sprocket you need to use a 1/8" endmill or smaller and the max spindle speed on the Hass is 7500 rpm when I should be running said endmill at 15000 rpm. So you have to turn the feed down. Also our 1/8" endmill is set in it's tool holder with just over 1" of stickout for clearance reasons with the parts we make and tool deflection doesn't help.

I would suggest:

Get a split point drill smaller than 1/8" and peck drill around the perimeter leaving a margin smaller than 1/16" for the final break out. Drill straight down so deflection is less an issue. Then when you cut out you'll have less material to engage the end mill dragging it in different vectors as you cut the sprocket parallel to the machine deck.

This could be a little complicated to setup in CAM software. I would suggest doing the drill pass as one operation, then I assume your Haas has an ATC, change for the end mills and complete the cut out.

Also there are Haas spindles faster than 7,500RPM. The price you pay for ignoring the speeds and feeds is really the tool life and as the tool wears you pay for that in quality of cut. Disengaging the some of the cutter would likely increase the tool life at a less than perfect feed and speed.

Best of luck with it - I am sure this operation is within the capability of whatever Haas you have I've done it before.

[RoboChair]

Originally Posted by Aboudy Dairi

What are your typical cut parameters in aluminum? What size tool, speeds and feeds, width, depth? Im very curious now.

We like our 4mm single flutes at 21-24k rpm feeding in aluminum at 45-60 ipm full WOC and a DOC of 0.060"-0.100". We run a super fine mist of WD-40 as coolant so the sacrifice board won't swell.

I uploaded some videos just now to YouTube https://www.youtube.com/playlist?lis...xLLzZmv6MFiAnF

[Aboudy Dairi]

Originally Posted by RoboChair

We like our 4mm single flutes at 21-24k rpm feeding in aluminum at 45-60 ipm full WOC and a DOC of 0.060"-0.100". We run a super fine mist of WD-40 as coolant so the sacrifice board won't swell.

I uploaded some videos just now to YouTube https://www.youtube.com/playlist?lis...xLLzZmv6MFiAnF

Do you see any flex in the gantry when plunging, especially with the drill? How much did you end up spending on the router? I'm extremely impressed just by the footage you took.

[RoboChair]

Originally Posted by Aboudy Dairi

Do you see any flex in the gantry when plunging, especially with the drill? How much did you end up spending on the router? I'm extremely impressed just by the footage you took.

I want to mention that the videos are typical of the performance we have observed. I have pushed it far harder than that, but I have to keep my fingers at the controls and jockey the feeds at least until I find somewhere that it likes.

The gantry is absolutely solid, no flex. The Z-axis head and spindle does flex away from the gantry under heavy axial load, a result of the head geometry common to almost all routers. Because the head is cantilevered off the gantry it has a good amount of mechanical advantage to cause deflection, due to the spindle axis being offset from the X-axis linear guides. It's only really been an issue for us when drilling larger than 3/16" holes because of the force required to pull a good chip is a little much for it. The problem goes away when you do a lot of peck drilling or pre-drill the holes with something smaller first. We solved the issue by just using a smaller than 0.250" endmill and helical boring any hole size over 0.1875", which has the happy side effect of one less tool change. For gearboxes and the like we bore the bearing holes 5-15 thousandths under size and post-ream them on our drill press to get the perfect fit.

We spent $6,000 on it but only because we knew which options that we could skip and do ourselves cheaper, what we picked up from Velox wasn't exactly ready to plug and play.

We dropped the following features
No table top surface -$649 (Surfaced ours with extrusion from my work's old router table)
No CAD software -$189
Supplied our own computer -$725
No dust hood -$315
No table legs -$1695
I drove down on a business trip and picked it up on the way back, so shipping was free. -$625
What we did get was as follows
Vectric Cut2D Pro for CAM +$450 (highly recommended, dirt simple to learn and use)
Mach3 License +$210
3.5HP Porter Cable router for spindle Default
1/2" Precision Collet +$100
4-Axis Smooth Step Default
Quick Manual Tool Change tool holders x3 +$260 (Lets you run as if you had a tool changer with pre-zeroed tools)
5% Educational Discount
5% Promotional Discount (for asking them nicely to sponsor us)

The reason we worked to bring the cost down so hard was because we got a 6000 dollar grant for buying a CNC router. I would have liked the Velox table extrusions and the proper spindle, but I was fine for the listed reason and I knew I could buy a spindle from China for about a tenth the price.

[Fusion_Clint]

Originally Posted by RoboChair

Quick Manual Tool Change tool holders x3 +$260 (Lets you run as if you had a tool changer with pre-zeroed tools)

This would be great, do you have a link to them?

[RoboChair]

Originally Posted by Fusion_Clint

This would be great, do you have a link to them?

http://www.veloxcncrouters.com/#!pro...c-(tool-qmtc-3)

Or the super cheap option
http://www.amazon.com/Lather-Milling...rds=er16+chuck
downside is that it's a 12mm shank and not 1/2", you just need to cut/grind the shank down to a usable length. I haven't found a 1/2" shank for ER collets that was under $80 but 12mm shank is under $13, it's really weird.

[JohnFogarty]

Originally Posted by RoboChair

I want to mention that the videos are typical of the performance we have observed. I have pushed it far harder than that, but I have to keep my fingers at the controls and jockey the feeds at least until I find somewhere that it likes.

The gantry is absolutely solid, no flex. The Z-axis head and spindle does flex away from the gantry under heavy axial load, a result of the head geometry common to almost all routers. Because the head is cantilevered off the gantry it has a good amount of mechanical advantage to cause deflection, due to the spindle axis being offset from the X-axis linear guides. It's only really been an issue for us when drilling larger than 3/16" holes because of the force required to pull a good chip is a little much for it. The problem goes away when you do a lot of peck drilling or pre-drill the holes with something smaller first. We solved the issue by just using a smaller than 0.250" endmill and helical boring any hole size over 0.1875", which has the happy side effect of one less tool change. For gearboxes and the like we bore the bearing holes 5-15 thousandths under size and post-ream them on our drill press to get the perfect fit.

We spent $6,000 on it but only because we knew which options that we could skip and do ourselves cheaper, what we picked up from Velox wasn't exactly ready to plug and play.

We dropped the following features
No table top surface -$649 (Surfaced ours with extrusion from my work's old router table)
No CAD software -$189
Supplied our own computer -$725
No dust hood -$315
No table legs -$1695
I drove down on a business trip and picked it up on the way back, so shipping was free. -$625
What we did get was as follows
Vectric Cut2D Pro for CAM +$450 (highly recommended, dirt simple to learn and use)
Mach3 License +$210
3.5HP Porter Cable router for spindle Default
1/2" Precision Collet +$100
4-Axis Smooth Step Default
Quick Manual Tool Change tool holders x3 +$260 (Lets you run as if you had a tool changer with pre-zeroed tools)
5% Educational Discount
5% Promotional Discount (for asking them nicely to sponsor us)

The reason we worked to bring the cost down so hard was because we got a 6000 dollar grant for buying a CNC router. I would have liked the Velox table extrusions and the proper spindle, but I was fine for the listed reason and I knew I could buy a spindle from China for about a tenth the price.

Now this post is interesting. Where can you buy the cheaper Chinese spindle?
I'm pretty sure I might go the Velox route.

[Aboudy Dairi]

Originally Posted by RoboChair

Supplied our own computer -$725

I noticed this on their website too, but is it mandatory to send a computer to their shop in order to install software?

[Frank Neuperger]

Robochair,

What tolernaces (in aluminum) are you achieving with your velox setup?
Have you benchmarked your machine for accuracy or repeatability?
i.e. using an indicator , have it return to a reference surface in each of the 3 axis.

Does your CAM or controller allow you to map your lead screw to enhance accuracy? If so, how many points will it allow?
Did you have to adjust scale in any of the 3 axis after you set up the machine?
One or 2 lead screws to move the gantry (low axis) ?
Do the anti backlash nut assemblies require maintenance or periodic adjustment?
Also, which model and size Velox did you buy for $6k?

[asid61]

Originally Posted by RoboChair

We like our 4mm single flutes at 21-24k rpm feeding in aluminum at 45-60 ipm full WOC and a DOC of 0.060"-0.100". We run a super fine mist of WD-40 as coolant so the sacrifice board won't swell.

I uploaded some videos just now to YouTube https://www.youtube.com/playlist?lis...xLLzZmv6MFiAnF

Youtube's video stabilization makes it looks like you have a 5th axis.
Question: is it common practice to conventional mill instead of climb mill on routers, and why if so? It looks like you are conventional milling that video.

[Dale]

At FRC1540 we are just in love with our Shopbot Buddy. Ours is a 2' x 4' version. It handles aluminum and plastic with nary a hiccup.