PB8x2 RS485 full-auto feeder development

[Peter Betz]

Hello everyone,

 As we have eluded to a few times, I've been working on a feeder system for us. Anthony Webb has been invaluable in printing/ testing/ and providing feedback/ suggestions to accelerate the design as well as Mark Harris and Jason V. for their feedback and suggestions!

The feeder system itself is based on dual lane module blocks. For starters this is 2 8mm tape lanes. The design is 3D printable but only with an EXCEPTIONALLY good printer. I am going to experiment with CNC milling some bodies in the future as it takes 10 hours to print a dual lane assembly. 

Here is the model, the turn down at the front is for testing, this is still in the development phase.

     

The module features a single circuit board to run both lanes. The board has a ARM cortex M0 processor, twin light gates, RS485 transceiver, two toshiba motor drivers that drive 4 motors total, 4 buttons, grove connectors for daisy chaining (cheap and prevalent?). I have just made R2 of the board that now has additional connectors to allow encoder inputs. The polulu motors I am using have add on encoder boards that may turn out to be a useful option, so these new boards will be able to advance the tape by opto on the gear teeth or by a motor encoder. More to come once I resume testing.

In addition to the feeder driver boards (DRVR) I have developed a 485 transceiver board (XCVR) to interface with the computer and also integrated a high quality SMPS to power the feeder network through the grove connectors. 

Here are the boards:

Here are pictures of the actual physical boards/ feeders:

(Feeders printed in clear so you can actually see though parts of it)

V1 feeder boards:

V2 feeder boards:

So the feeders are "working", in the sense that you can send them messages over RS485 and they will advance by the number of requested holes.

Here is manual feeding:

Example of feeding video

The thing we are working on is the accuracy. As you can see in the following video it does't repeat the move very well. The V1 boards had a mistake and we were not able to control the PWM of the main motor (there is a pot on the board to control the PWM of the cover tape motor). We are expecting that if we can slow down the motor the accuracy should improve. Anyways, you can see what I'm talking about here in Anthony's video (which is triggering the feeder over RS485 through the XVCR board):

Example of feeder accuracy (drift)

I am also going to experiment with water jet cut stainless drive gears that I had made:

So there you have it, sorry I have been meaning to share this with everyone a long time ago but I've been super busy, I'm even rushing this post but I'm hoping you guys find it interesting!!

Peter.

[Peter Betz]

Oh and I forgot to mention that one dual lane module is just under 20mm wide. I think dual 12's might fit in the same footprint as well.....

Peter.

[SMdude]

Nice work Peter!
Perhaps to get better accuracy, are there any IR sensors that can be a closer fit to the tape drive/encoder?
Or perhaps print some small covers for the existing ones.

Any rough guestimates on what the parts cost is for one dual lane?
I need to do something with feeders soon...

Cheers!

[Peter Betz]

Thanks!

Now that we have the new boards we will be experimenting more with the accuracy. between the PWM on the main motor and also experimenting with motor encoders I think we will be accurate sooner than later. The design of the boards and the feeder may seem simple, but you would be floored to know the amount of hours and iterations it took to get even this far. 

As far as cost, I think we are around $50/ $60 per dual lane. The design will be fully open source but I was also probably going to offer them for sale on the website. Once we hammer out the design, we will work on the pricing. 

Peter.

[SMdude]

Simple?? Haha! Even the simplest of things can sometimes actually be quite the opposite!

$50 to $60 as a rough guestimate (not going to hold you to it)cost for diy, is not too bad given it is all in one.

Keep up the good work :D

[Jason von Nieda]

Great work Peter and Anthony! It's been fun following the development of this feeder and I'm really looking forward to trying one out some day!

Jason

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[Peter Betz]

Hello All,

Just wanted to say that this feeder project isn't dead. I finally got my new 3D printer working (based on the important pieces of the i3 MK2, but on a waterjet aluminum frame and linear rails). Just printing the cases to test the feeder with the motor mounted encoders. 

Peter Betz

Betz Technik Industries Ltd. 

BETZtechnik.ca

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[Matt Brocklehurst]

Hi Peter

Slightly off topic but is this printer design one of your own? And what advantages does it have over the Prusa or p3steel?

Matt

Sent from my iPhone

On 12 Aug 2017, at 01:37, Peter Betz <betzt...@gmail.com> wrote:

Hello All,

Just wanted to say that this feeder project isn't dead. I finally got my new 3D printer working (based on the important pieces of the i3 MK2, but on a waterjet aluminum frame and linear rails). Just printing the cases to test the feeder with the motor mounted encoders. 

To view this discussion on the web visit https://groups.google.com/d/msgid/openpnp/996F803C-2D20-4399-B2B0-63D707CDBD46%40gmail.com.

[Peter Betz]

Hi Matt,

It takes the magic of the new MK2 and puts it on a professional chassis, like I was saying hiwin linear rails, 4 long carts under the bed, did stress studies and shape optimization on the bed plate, I wanted no vibration. It is crazy rigid. I've been printing at 200% speed with no ill effects etc. Works with the stock firmware which is critical. 

Anthony and I worked on the design together. We both couldn't accept the standard frame and motion components, but couldn't deny the print quality of the MK2 (I know, it's a Prussia, but the results are spectacular stock). We also have a currently unreleased bond tech geared extruder that is amazing. 

Disregard the screen and wiring. The electronics are designed to go under the frame (out of sight) but I need to extend some wiring so it is all up top for now. 

Peter Betz

Betz Technik Industries Ltd. 

BETZtechnik.ca

To view this discussion on the web visit https://groups.google.com/d/msgid/openpnp/61C9450C-1968-4585-84E9-6038E643F846%40mattbrocklehurst.co.uk.

[Matt Brocklehurst]

Hi Peter

Wow looks good :) btw as I’m sat next to it here’s my p3...  so need to finish setting up smoothie and try it out!

Do you plan to release the design or sell the frame?

Cheers 

Matt

Sent from my iPhone

On 12 Aug 2017, at 06:21, Peter Betz <betzt...@gmail.com> wrote:

Hi Matt,

It takes the magic of the new MK2 and puts it on a professional chassis, like I was saying hiwin linear rails, 4 long carts under the bed, did stress studies and shape optimization on the bed plate, I wanted no vibration. It is crazy rigid. I've been printing at 200% speed with no ill effects etc. Works with the stock firmware which is critical. 

Anthony and I worked on the design together. We both couldn't accept the standard frame and motion components, but couldn't deny the print quality of the MK2 (I know, it's a Prussia, but the results are spectacular stock). We also have a currently unreleased bond tech geared extruder that is amazing. 

Disregard the screen and wiring. The electronics are designed to go under the frame (out of sight) but I need to extend some wiring so it is all up top for now. 

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To view this discussion on the web visit https://groups.google.com/d/msgid/openpnp/291E02F8-2BE4-430F-A786-41A9FE89170B%40gmail.com.

[Peter Betz]

Looks good! I'm happy to share the design, need to update some parts of it first though!

Peter Betz

Betz Technik Industries Ltd. 

BETZtechnik.ca

On Aug 11, 2017, at 11:49 PM, Matt Brocklehurst <ma...@mattbrocklehurst.co.uk> wrote:

Hi Peter

Wow looks good :) btw as I’m sat next to it here’s my p3...  so need to finish setting up smoothie and try it out!

Do you plan to release the design or sell the frame?

Cheers 

Matt

To view this discussion on the web visit https://groups.google.com/d/msgid/openpnp/0D9B1BEF-3C22-49B2-8AB7-B33C038B1EA6%40mattbrocklehurst.co.uk.