[talonosi]

Thanks for the questions all of you have answered over the past month, and to CNC Router Parts for your quick responses to my questions. I recently placed my order for a CNCRP PRO 48696 machine. I initially planned on the 48x48 because my primary use will be cutting small approx. 6x6" pieces of plastic, however when I started considering the benefits of cutting full sheets of plywood for special projects around the shop.

I don't have the kit yet but I'll tell you my plan and what I have coming.

Parts from CNCRP.

• PRO 4896 kit
• 4 axis DIY NEMA 34 electronics kit
• Pro complete cable track kit
• Auto Z Touch Plate
• Enclosure + assembly kit
• Ethernet Smoothstepper
• Limit switch kit

I decided to go for a spindle instead of a router. I considered a water cooled 2.2 KW spindle but wasn't thrilled with adding water cooling, and was concerned about the the long term durability of the air cooled 80mm spindles. I ended up going for an air cooled spindle from UGRA CNC, the price was quite a bit higher than standard 80mm air cooled spindles, but I liked the housing and the run out testing done before it ships.

I also ordered the PMDX 107 to allow me to control the VFD running the spindle. For the VFD I chose a GS3 from Automation Direct. I purchase quite a bit from them and have really grown to love their documentation provided, better than anything I've seen on other imported electronics equipment. I use the same VFD on a manual milling machine so have experience wiring it an programming it. I'll purchase the enclosure and other items from them.

I typically error on the side of overbuilding everything in the shop, so I will be building a pretty heavy duty base to hold the router. It will be made primarily of 3" square tubing with a 3/16" wall, gusseted with 1/4" plate. I've attached a drawing of it here. I think it will be plenty strong while still allowing me to us the area below the shelf for storage. The gussets aren't shown in this drawing. This base should weigh around 450 lbs when complete.

Attachment 271538

The base will also have leveling feet and mounting points for 4 trailer jacks to allow me to move it when required.

That is the plan so far! I'll be sure to update it as parts come in.

[talonosi]

Attachment 271544

I realized that drawing didn't have the upper cross members that run down the center. I plan on attaching each of the aluminum cross members to it to help reduce flexing and vibration.

[Scottart]

I am on my 2nd weekend of my CNCRP 48 96 pro build. I used their bolt up frame. I am sure the welded version will serve you well. The kit provided is very good, i just started testing today an dean out of time. this past weekend. I have few questions about alignment and the interface between the 34 controls and the MACH 3 controller. Anxious to watch what you do.

[talonosi]

I'll certainly try to keep you up to date.

Parts have started to trickle in! I just got my spoil board surfacing bit from ToolsToday. Mini Insert Spoilboard Surfacing, Rabbeting, Flycutter and Bed Skimming CNC Router Bit with Scorers, 2 + 2 Design -Toolstoday.com-, this thing is pretty sweet looking, I can't wait to try it out.

Attachment 271616

I expect the spindle and the first batch of electronics (VFD, enclosure) to be here this week, as well as an the PMDX 107. Hopefully the router kit will be in some time next week. I won't start building the welded base till I have the base of the router built so I know the dimensions are correct.

[talonosi]

I'm having a bit of a problem deciding how to run the electronics for both the BOB enclosure (the kit I ordered from CNCRP), and for the VFD Enclosure. In the past several electrical components I've built for the shop I've built in a latching relay circuit with a master start switch and an E-stop button that actually cuts power to the entire box. It appears that the CNCRP box doesn't have anything like this (Or even a manual switch). Is this correct? If so, it seems to me that you wouldn't want to leave the enclosure plugged in all of the time, so that means you would need to unplug the box each time you are done with it. Is this what you guys do? If this is the case, I will install either a latching master relay or a manual switch. One nice thing about using a master relay is that you can install as many E stop switches as you want, each of which can cut the power to the entire machine. (In my mind, this lower level E-stop switch seems safer, but may be an overkill). It also ensures that if the machine loses power, it stays off when the power comes back on.

Something for me to think about.

[talonosi]

I received my PMDX 107 today and got a notice that the aluminum extrusion has shipped! I look forward to getting it! Now I really need to clear some space for the project.

[talonosi]

-Electronics update-

After doing a bit of research, I decided to put a contactor that can cut power to the VFD when I need to change router bits. I'll likely run remote E-stop type switch to to an accessible location that cuts power to the contactor while leaving the power to all of the other control circuitry. This should be a guarantee that I can change a bit without risk of the spindle turning. Now my concern is trying to wire in some type of interrupt into the Mach 3 so that when the spindle power is turned off, it knows it and won't try to drive a stationary bit through a chunk of wood. Any thoughts on that?

I suppose I could make an auxiliary contact on the contactor function as part of the E-Stop Circuit or machine hold circuitry into the BOB. This way when the power to the spindle is off, it will automatically lock out movement of each axis, which will serve as another level of safety ensuring that somehow the machine won't start moving while you have your hands near it. However, I don't want it to cut power to the motors, I just want it to hold them in a fixed position. I need to verify that is how it will work.

[talonosi]

Yesterday I received the aluminum extrusion. That gantry is stout! I laid out a few pieces to verify the dimensions of my base and ordered the materials. The metal should be cut and ready to weld up sometime next week, but I'm not sure when the welding will get done (Probably will take us a week or more to get to it). I'll post up more info/pics as I get the base finished up. I'd be happy to provide drawings/BOM to anyone interested.

I also received the spindle from Ugra CNC. It was packaged very well. I tested the runout with an indicator testing the inside of the collet taper. I got a max runout of .00015. I'll see about testing the TIR when I get a chance a little bit later. I don't have a pin that I trust to do the test, so I may do it with a 1/2" end mill.

I finished up the planning of the electronics. I think I should be able to wire in some good monitoring and failsafes into the system.

Here is a pic of the 3 packages of aluminum extrusion
Thanks!Attachment 272226

[grubscrew]

How do you plan controlling the vfd with mach 3? I use a usb-485 converter with the french plugin, and if i kill power to the vfd and then turn it back on, mach 3 will not comunicate with the vfd until I restart mach 3. What I have done is wired in a e-stop to the pmdx-126 BOB, hitting it will create a alarm on mach 3 not allowing mach 3 to trigger the vfd.

[talonosi]

How do you plan controlling the vfd with mach 3? I use a usb-485 converter with the french plugin, and if i kill power to the vfd and then turn it back on, mach 3 will not comunicate with the vfd until I restart mach 3. What I have done is wired in a e-stop to the pmdx-126 BOB, hitting it will create a alarm on mach 3 not allowing mach 3 to trigger the vfd.

I'm not familiar with the plugin you are using, I'm assuming it communicates via modbus? Is that correct?

I am going to use the PMDX-107 which is an add-on card for the PMDX-126. Basically this allows mach to communicate speed and on/off control via a PWM singal from Mach. I think the PMDX-107 takes the PWM signal and ouputs a voltage proportional to that speed, similiar to how a standard pot might be used to control the output of the VFD. I should also be able to allow the VFD to send a fault signal to the PMDX-126 should it have an issue. I plan on using my VFD output so send an 'At Speed" signal to PMDX-126 so that I never attempt to cut with a stationary spindle. I plan on having a safety hold on the machine for manual tool changes that stops all outputs from the PMDX-126 and removes power from the VFD via a contactor, so I need Mach to be able to identify this situation and never attempt to run a program with the spindle power disconnected.

PMDX has an application note that covers this arrangement.

PMDX.COM - Products for CNC and motion control applications

[talonosi]

The majority of my order from Automation direct came in today. Everything but the enclosure for the VFD. With this order comes several E stop switches, a large contactor for the VFD, Various relays for control inputs/outputs and for main power to the steppers, and the VFD. Now I need to start working on a wiring diagram while I wait for the kit to come form CNCRP. I ordered it two weeks ago so it should be shipping any time!

[Advance501]

Talonosi,

I am currently putting together a PRO4848 machine with many of the same electronics you are using for your build (PMDX 126 and 107). I came across this great article while researching how to safely operate and integrate my VFD (Hitachi WJ200-022SF) and spindle:

Feed your VFD with the right power | Motors/Drives content from Machine Design

My initial plan for changing tools safely was just like yours (cut the main power to VFD via switch or contactor). While this method should be the ultimate in safety, the high frequency of cycling the drives main power might lead to premature drive failure. Check out the "Approaches that spell trouble" section of the article.

My current plan is to keep the VFD powered up as long as the machine is being used. There are many great logic inputs and outputs from the VFD and Mach3 that can be combine to build redundant levels of safety into the machine.

[talonosi]

Talonosi,

I am currently putting together a PRO4848 machine with many of the same electronics you are using for your build (PMDX 126 and 107). I came across this great article while researching how to safely operate and integrate my VFD (Hitachi WJ200-022SF) and spindle:

Feed your VFD with the right power | Motors/Drives content from Machine Design

My initial plan for changing tools safely was just like yours (cut the main power to VFD via switch or contactor). While this method should be the ultimate in safety, the high frequency of cycling the drives main power might lead to premature drive failure. Check out the "Approaches that spell trouble" section of the article.

My current plan is to keep the VFD powered up as long as the machine is being used. There are many great logic inputs and outputs from the VFD and Mach3 that can be combine to build redundant levels of safety into the machine.

Thanks for the link. I did a bit of research on that as well and contacted the drive manufacturer to see what they had to say. In my specific case I will rarely do tool changes with the exception of the occasional project for the shop (not related to production). Now that I've read that article I'll be sure to wait 2-3 minutes before I turn the VFD back on.

However, since I was cautioned by Automation Direct about frequent on/off cycles of the VFD I did have a contingency plan for those rare situations where I am changing tools frequently for a specific job. The plan was to wire in a simple switch that enable/disables output of the VFD (Probably what you are planning as well based on your description). I believe this to be a pretty dang safe way to do a tool change, but I want the ultimate safety method to be cutting power to the drive.

Here is what my typical tool change cycle will be.
-Turn VFD Off via switch mounted on VFD Enclosure
-VFD Contactor auxiliary relay send signal to the PMDX-126, disable all output (This prevents an inadvertent movement of the machine while the operator is working with the spindle, but also ensures that the machine won't attempt to run a program with a stationary spindle).
-PMDX-126 sends signal to Mach that it is in a "machine hold" state (Still haven't figured out how I'm going to implement this in Mach).
-Operator changes tool
-Operator turns VFD Back on, Removing the "Machine Hold" state from the PMDX-126 and Mach.

An alternate method, which at least elminates Mach and the PMDX-126 as possible failure points is this.

-Operator turns VFD Output switch to "Disable"
-This switch also send signal to the PMDX-126 to enter a "Machine Hold" State, which also send it to Mach 3
-Operator changes tool
-Operator turns the switch to "Enable" which allows output to the VFD and removes the machine hold signal.

In either case, I plan to modify the M3 macro so that it waits for an input triggered by the VFD "At speed" signal. That way, even if the machine hold aspect of the PMDX-126 fails (unlikely), the machine will not proceed with the program until the spindle reaches to proper speed. (Although I suppose this method could still fail if the VFD failed to receive the signal from the PMDX-107, since it would still output the "at speed" signal because it thinks it is supposed to be standing still. I could account for this by making the M3 macro wait for "At Speed" but not progress if the drive says "zero speed", that is, unless the requested speed is 0).

What method are you planning on using?

[Advance501]

I am still acquainting myself with the vast 420 page manual for the WJ200 drive. The WJ200 has an fully configurable internal relay that I am planning on using with its alarm/trip function. When the drive encounters one of many possible errors (over temp, over current, overload, etc.) it will initiate a spindle stop command and enter a state where the spindle cannot be run until the alarm is reset. I plan on using this relay with the PMDX-126's estop circuit so if the drive encounters an error and enters the alarm/trip state, mach3 will do the same. This relay is open when the drive is powered down, which means the estop circuit is active. I would add a bypass switch that bypasses the relay contacts, and allow me to move the machine without the drive being powered.

I am still undecided with regards to safe tool changes. There are many options available. The WJ200 has the ability to rig up an external alarm/trip and reset switch. I was thinking about using a switch to manually enter the drive into an alarm/trip state, which would disable its ability to run the spindle. Entering this alarm/trip state would also open the drives relay contacts, which would initiate an estop in mach3, disabling its outputs. It should be completely safe for me to change a cutting tools at this time. I could add another redundant level of safety by utilizing the PMDX-126's K2 relay and the geckos motor disable function, but this would be going too far.

This is the switch I am currently looking at utilizing:

http://www.ebay.com/itm/ATI-DPB22-22...item4ad7ead41a

Pressing the OFF button would manually trip the alarm on the WJ200 and light the LED lamp on the switch using the alarm output function. Pressing the ON button would reset the WJ200's alarm and close its relay contacts. The drive should now be ready to operate and the PMDX-126's estop circuit should be closed. Pressing reset in mach3 will enable the machine's outputs.

I like your VFD "at speed" input idea. There are a few programmable output functions that I saw in the WJ200 manual that might work for this. There is a configurable frequency arrive signal and a zero Hz speed detection signal.

[FoxCNC1]

what are you guys trying to accomplish or prevent? that VFD turning the spindle on while you are changing a tool?

[talonosi]

what are you guys trying to accomplish or prevent? that VFD turning the spindle on while you are changing a tool?

Yes, that is it. But the cost/risk is higher if this machine is going into a production environment where it may be used by multiple operators.

[talonosi]

I am still acquainting myself with the vast 420 page manual for the WJ200 drive. The WJ200 has an fully configurable internal relay that I am planning on using with its alarm/trip function. When the drive encounters one of many possible errors (over temp, over current, overload, etc.) it will initiate a spindle stop command and enter a state where the spindle cannot be run until the alarm is reset. I plan on using this relay with the PMDX-126's estop circuit so if the drive encounters an error and enters the alarm/trip state, mach3 will do the same. This relay is open when the drive is powered down, which means the estop circuit is active. I would add a bypass switch that bypasses the relay contacts, and allow me to move the machine without the drive being powered.

I am still undecided with regards to safe tool changes. There are many options available. The WJ200 has the ability to rig up an external alarm/trip and reset switch. I was thinking about using a switch to manually enter the drive into an alarm/trip state, which would disable its ability to run the spindle. Entering this alarm/trip state would also open the drives relay contacts, which would initiate an estop in mach3, disabling its outputs. It should be completely safe for me to change a cutting tools at this time. I could add another redundant level of safety by utilizing the PMDX-126's K2 relay and the geckos motor disable function, but this would be going too far.

This is the switch I am currently looking at utilizing:

http://www.ebay.com/itm/ATI-DPB22-22...item4ad7ead41a

Pressing the OFF button would manually trip the alarm on the WJ200 and light the LED lamp on the switch using the alarm output function. Pressing the ON button would reset the WJ200's alarm and close its relay contacts. The drive should now be ready to operate and the PMDX-126's estop circuit should be closed. Pressing reset in mach3 will enable the machine's outputs.

I like your VFD "at speed" input idea. There are a few programmable output functions that I saw in the WJ200 manual that might work for this. There is a configurable frequency arrive signal and a zero Hz speed detection signal.

Yeah, it took me a while to get familiar with my VFD of choice. That is why I went with the same model I used about a year ago so I wouldn't have to relearn the VFD, they can be complex when you don't deal with them on a daily basis.

Here is a form post that talks about safety for VFDs during a tool change.

http://www.cnczone.com/forums/diy-cn...ging-bits.html

I have been researching VFD disconnects that are designed to be placed between the VFD and the motor. It sends a stop signal to the VFD before it disconnects the main power. This may be the ultimate solution, although it will cost a few hundred dollars. It is the ultimate in safety yet allows the VFD to remain on constantly. I may look more into this now that I know there are products made for the purpose (I looked into it earlier, but figured I'd have to wire up my one using time delay relays and such, not something I wanted to get into at my experience level).

Here is an example (Although this one is only rated for 60hz, when our spindles will likely be running at 400).

Hubbell HBLDS3VFD Disconnect Switch for Variable Frequency Drives - Crescent Electric Supply Company

[talonosi]

I got the notice of shipment today! My kit is on its way! I think I'll see it Monday or Tuesday.

I also picked up the metal for the base. As I said earlier, it is made of 3" square tubing, 3/16" wall and should weigh around 450 lbs.

[landarts]

Nice I love the metal based table. You will be very happy with the rigidity of the table. How are you going to finish it? If you are not familiar with Hammerite paint it is a great product that flow well and you put it on with a brush.

[talonosi]

I just thought I'd post an update. I have the base completed and painted and finally started assembling the router today. As I've said before, The base weighs in around 450 lbs and is very stout! I'm glad I went big. The base ended up costing about $600 in cost of materials and cutting, but I could park a car on this thing.

Here is a picture of it completed.