Design & Build of Frankenrouter

Hi All - In another thread there has been discussion about backlash of belts and since Frankie uses belts and I have been wanting to do this particular model for some time I did it this morning. The aim is to determine how many teeth distribute the load on the belt. So I modelled a straight bit to keep it simple. The PU belt is the same size as an AT5 belt but the result will be similar on all tooth shapes. The Al "rack" has a stiffness of 70,000MPa the PU is 6.0Mpa and the steel "belt" is 11,700MPa. This is the equivalent stiffness of the 2.5x1.5mm area of the cords that run through it, calculated from the quoted specific stiffness of an AT5 belt of 17605N/mm width. The cords bundle is a 7x3 with an outside dia of 0.9mm which means there is approx 1 cord per mm width of belt. My 10mm belts have 10 cords and the 16mm I have has 17 cords. I have used friction co-efficient of 0.2 at the contact surfaces. In the images you can see that the first tooth does most of the work, the second a bit the third not much then past that they are not doing anything. So if you assume that 4 teeth are doing the load transfer you conservative. this model uses zero clearance teeth as I couldn't find the actual clearance of the teeth but this would not change the trend. Peter

Thanks for sharing Peter. The images really help with visualising what is happening with the teeth under load.

Wet morning here - Today I have worked through the parts, starting to think about manufacturing and assembly details. Adding space here, taking it away etc, I have put the base motor into the base and fixed a few things in the saddle. I'm worried about dust and loading damage to the base belt as its horizontal. So I am going to extend the base out over it to act as a cover and protector. The thick tool plate is growing on me & I've added a couple of brackets to the gantry legs. Nearly at detailing stage. I'd like to do the base as an isogrid but 45degs is harder to do, but then nothing ventured nothing etc etc... Peter

Hi All - I have added the ledge over the drive and installed the two candidate Z axes. The price of the steel Z is quite good plus it has a short stack. I have stretched it to take a full 2400mm sheet. I will make the base in two halves and bolt them together in the middle. The wall will be continuous. I have to adjust the steel Z tool plate height. I'll start rebuilding the detailed model now. Peter

Quote:

---

Originally Posted by JayneV

Thanks for sharing Peter. The images really help with visualising what is happening with the teeth under load.

---

A straight pull like this is not a true simulation of what is happening ,when the belt is going around a Timing Pulley, a completely pointless exercise also, if the profiles are not a true representation of the real parts Belts and Pulleys measurements.

Ah Mactec - You have been so good lately, but now.... Thanks for your opinion. Peter

Morning All - I'm about to start redesigning the bench's so decided to do a quick FE on diagrid vs orthogrid. In bending the ortho at same weight wins but the dia is much better in torsion. In bending the dia is 5.5mm vs the ortho at 4.6mm not much diff really. In torsion the ortho is 11mm vs the dia at 7mm thats a delta. So I put in an extra longitudinal so it becomes an isogrid and then its bending was the same as the ortho 4.7mm iso vs 4.9mm ortho and the its torsion iso 6mm vs 11mm ortho. So should look at that to see if I can do it easily... My other thought is that I need a structure that lines up with the wall structure for bolting.. Hmmm ortho wins that one.. Peter

Evening All - I'm about to place an order for some laser cut parts but haven't come up to min order value so I'll get Frankies Z axis tool plates cut, to top up the order. I've added 120mm to Scoots tool plate. This is wider then the AL/ply/Al version I had but I can make the machine a little wider to get that back... Have to sort some holes and the ballscrew then get it into the GA. But the GA is being rebuilt so a bit of a CAD jigsaw at the moment... Starting to get excited with this design will be a good machine....Peter

Hi All - I've been contemplating the overall size of Frankie and the structure of the bench. In my reorganisation of parts yesterday I came across some casters with adjustable height feet I'd forgotten about. So I've decided to make the machine base and bench as one. Still undecided about the envelope. I had an interested boat builder but he has decided he wants a full sheet machine so maybe next one. So I think the "base" will be 2400mm long and the machine will fit on that leaving a small space for the laptop.... Soon to be back into CAD. Peter

Hi All - I've ordered the 2 tool plates and I'm having them painted red as in the render attached. I've added a wall to the end to put the electronics on. I may even use an enclosure this time. I tend to leave the electrics in the open... Frankie will be about 2m long leaving a space for the laptop on the "bench". Not sure whether to have a bench and a machine or integrate them yet. So I'll start Frankie No5 now... Peter

Morning all you sleepy lot - I have worked through Frankie and sorted a few things. F5-0 will have a two piece bench. This will make transport easier. The saddle, as always is a juggle and will be made as a CSA-UHPC cast part or a CF infused part. The Gantry will be laminated ply/aluminium and instead of placing the computer on the "bench" I'll make a sidetable for it on the end of the machine. So now I can get serious and detail Frankie out.... not near my computer at the moment that's about a week away... Peter

Seems the image did not attach - - Peter

Hi All - I'm back at my desk and looking forward to some workshop time. Been away for nearly two weeks and I miss the shed... So Frankie's rules of engagement, Frankie5-1:
1) use as many Tetra Motion surplus parts as possible
2) make as many parts as possible in-house
3) Have used the new steel laminated tool plate design to get to a minimum order value. I pick these up this week
4) Use up some 2mm aluminium sheet I have as laminated parts
5) optimise size around 2400mm long sheet
6) Maybe try the xPro V5 system as my first GRBL machine. Need to understand its software capabilities before I do this. Especially for 3D work. Some reading there to do...

So tidy up the parked projects and get all the wheels rolling again... Peter

Morning All - I'm planning the electronics for Frankie and would like to run it wirelessly. I have a 5axis std BOB has anyone run these wirelessly? I'd use a UC100 or another UC motion controller. I have a ruggedised W7P notebook to run it and would like it to be cable free.... any thoughts out there appreciated.... I'd planned to use a 60V PS I have but its only 3A, thought it was 10A. So I have a 36V 10A so that will be fine for this build... I'll get a combined 5V - 24V PS for the logic and brake supply....Peter

Evening All - Tomorrow I pick up the tool plates for Frankie. Qld has opened its borders so I can get to the metal shop that does these for me... Then the Z axis can be detailed out.... Peter

Quote:

---

Originally Posted by peteeng

Morning All - I'm planning the electronics for Frankie and would like to run it wirelessly. I have a 5axis std BOB has anyone run these wirelessly? I'd use a UC100 or another UC motion controller. I have a ruggedised W7P notebook to run it and would like it to be cable free.... any thoughts out there appreciated.... I'd planned to use a 60V PS I have but its only 3A, thought it was 10A. So I have a 36V 10A so that will be fine for this build... I'll get a combined 5V - 24V PS for the logic and brake supply....Peter

---

I have a Tablet similar made by RCA that I have used, more an experiment than a machine control, I used it with the UC100, and it worked very well, wirelessly I don't know if that would be a good idea. you can use a pendent wirelessly

This RCA has a detachable keypad, Windows10 and has a USB port. work really well

Hi Mactec - I sent a note to Balazs at cncdrive and he did not recommend using wireless due to possible latency. Doesn't mean its not possible. A pendant is the answer I suppose. My main aim at the moment is to complete the Z axis assembly... Peter

So with the RCA unit the USB port is in the keypad so it stayed stationary? The touchscreen then is used as the pendant as it communicates with the keyboard? If so I'll look out for such a device next time...

Quote:

---

Originally Posted by peteeng

Hi Mactec - I sent a note to Balazs at cncdrive and he did not recommend using wireless due to possible latency. Doesn't mean its not possible. A pendant is the answer I suppose. My main aim at the moment is to complete the Z axis assembly... Peter

So with the RCA unit the USB port is in the keypad so it stayed stationary? The touchscreen then is used as the pendant as it communicates with the keyboard? If so I'll look out for such a device next time...

---

No, the USB is in the computer along the side of the touch screen.

It also has a MicroSD card slot, and this is what I load the different CNC control software on, then you don't have to use the hard drive in the computer.

The Keypad attaches with a magnet and is not needed, but does make things easy when you want to load new software Etc.

Windows 10
Intel Celeron Processor, 2 GB RAM
12.2" Capacitive Touch TFT, Display Resolution (1920 x 1200) IPS
Built-in Speaker, USB 3.0, Bluetooth 4.0, HDMI Out, Wi-Fi to connect to Internet, 64-GB Internal Memory
MicroSD card slot support up to 128G (card not included)
Rechargeable Up to 6-Hours Battery Life
Front 2MP Camera, Rear 2MP Camera

Afternoon all you lot - Today I picked up the tool plate and adaptor for Frankie. I shall lap them together and then bond them together with PU adhesive to form an I beam. I think its amazing that two pieces of 3mm steel like this is equivalent to a solid steel piece about 80mm thick in bending... I've sorted a few more surplus parts so now I want to finalise the Z axis and the bench in CAD and start making the bench.... Peter

Quote:

---

Originally Posted by peteeng

Afternoon all you lot - Today I picked up the tool plate and adaptor for Frankie. I shall lap them together and then bond them together with PU adhesive to form an I beam. I think its amazing that two pieces of 3mm steel like this is equivalent to a solid steel piece about 80mm thick in bending... I've sorted a few more surplus parts so now I want to finalise the Z axis and the bench in CAD and start making the bench.... Peter

---

Yes C-Chanel used like this can be very strong, what are the dimensions, you are using, as you can get this off the shelf, or even in Fiberglass C-Chanel, C section like this is used a lot in building construction so there are many sizes available, I like this c-section the best, these are extruded so the dimensions are quite accurate