Cherry Pi III Is Available

Hello David,

I used a 47k and 15k resistor as you suggested. Gives me 2,9V and works like a charm.

Thanks for your help.

BR,
Simon

double post

Edited 1 time(s). Last edit at 08/06/2015 05:35PM by YDKJ.

Quote
YDKJ
Hello David,

I used a 47k and 15k resistor as you suggested. Gives me 2,9V and works like a charm.

Thanks for your help.

BR,
Simon

Darn, now I can't sell you one of my IR sensor boards!

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Quote
pugzor
Ends up my filament was slipping. Fixed it up though. Had to shave a bit off some of the assembly because clamped down the bearing wasn't actually connecting with the top of the filament...

Anyway, now it's printing freaking AWESOMELY.

One question though; what retraction are people running? I think that's the only thing that's off for me now as my models are really messy when it jumps between areas.

In Cura I use 3mm and 20mm/s

Hi Andy, quick question. I'm building the wonderfull cherry pi IIIS and have the same "clone" metal hotend (that you supply with the kit I believe?). What thermistor table in Marlin do you use with this hotend?

Hi Nilez

I use the standard '1' used for a normal 100k device. Seems to work fine.

Andy

It's not the greatest, as I seem to still have a problem with my filament slipping... but it's getting there!

Hey guys,

Thanks Andy thats good to know! Hey Pugzor, great you're still hanging in and perfecting your Cherry Pi despite those bumps on the road getting there that I've read about in this thread!!

I'm starting to pay attention to my Cherry Pi delta once more, with the aim of sorting the problems that bugged me previously.

The first one is to do with the 'umbilical cord' leading to the effector:



Originally I used one of dc42's IR sensors, but had problems with an uneven print. David had mentioned that having the sensor some way from the nozzle could lead to errors in some circumstances, so as an experiment I replaced it with a mechanical switch activated when the nozzle touched the print bed. This worked better - but, following some different problems with the mechanical switch, I don't think that there was anything wrong with the original IR sensor setup.

What's happening at the moment is that when the effector moves to the front, the tension/stiffness in the umbilical cord is pulling on the hot-end platform and operating the limit switch. This means that I have to use greater spring tension on the Z-limit switch than I would like. With the IR sensor, I suspect that the umbilical was pulling the effector at the front of the bed and pushing when it was at the back, leading to false readings in the Y axis - and I was getting prints that were fat at the front and thin at the back, which matches my theory. The prints were fine in the X axis, with an even layer.

So, after that long-winded explanation, I would like to know how others have set up the bowden tube and wiring so that it doesn't influence the effector. I have another IR sensor board on the way, so I'd like to get this sorted!

Edited 1 time(s). Last edit at 08/24/2015 06:15AM by David J.

Hi David

I suspect your issue is caused by the spiral wrap that you have used to contain everything. This leads to a 'stiff' umbilical. I always use the braided cable sheath available from various Ebay suppliers. It's a bit more of a 'pfaff' to use but it's much more flexible.

[www.ebay.co.uk]

I love the re-designed rod holders btw. They are a great way to add more build height for free. You will have to send me the .stl for them


Regards

Andy

Edited 1 time(s). Last edit at 08/24/2015 07:21AM by AndyCart.

I found that braided stuff to be more trouble that it's worth! It frays at the ends as soon as you touch it, and it's impossible to make changes to the wiring later on. Oh - and I had the trouble I described earlier with the braided stuff...

I'm wondering about modifying the layout so that the bowden tube goes straight up, into a U-bend and straight down again - but I suspect that its springiness will make it go everywhere within the frame.

You're welcome to use the carrier design - you'll find it at Thingiverse. It's in OpenSCAD, so easy to modify (if you know SCAD, that is!). It's a mod of Maso's design, so full credits to him - I just changed the belt fixings.

Edited 1 time(s). Last edit at 08/24/2015 10:00AM by David J.

Quote
David J
What's happening at the moment is that when the effector moves to the front, the tension/stiffness in the umbilical cord is pulling on the hot-end platform and operating the limit switch. This means that I have to use greater spring tension on the Z-limit switch than I would like. With the IR sensor, I suspect that the umbilical was pulling the effector at the front of the bed and pushing when it was at the back, leading to false readings in the Y axis - and I was getting prints that were fat at the front and thin at the back, which matches my theory. The prints were fine in the X axis, with an even layer.

So, after that long-winded explanation, I would like to know how others have set up the bowden tube and wiring so that it doesn't influence the effector. I have another IR sensor board on the way, so I'd like to get this sorted!

I use spiral wrap too, but it is a thin clear polythene type and it doesn't seem to make the bowden tube too stiff. Even so, I may try leaving gaps between the turns to increase the flexibility. Now that I've switched to 24V electronics, I could use thinner wires for the heater, which should help with flexibility.

If you are using Duet electronics, you can now configure height error offsets at each of the bed probe points in the bed.g file, to compensate for effector tilt that you can't eliminate. The trigger height errors on my build due to effector tilt are as high as 0.3mm in some areas of the 300mm diameter bed. I still haven't worked out what is causing the tilt.

Edited 1 time(s). Last edit at 08/24/2015 12:34PM by dc42.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Quote
dc42

Quote
David J
What's happening at the moment is that when the effector moves to the front, the tension/stiffness in the umbilical cord is pulling on the hot-end platform and operating the limit switch. This means that I have to use greater spring tension on the Z-limit switch than I would like. With the IR sensor, I suspect that the umbilical was pulling the effector at the front of the bed and pushing when it was at the back, leading to false readings in the Y axis - and I was getting prints that were fat at the front and thin at the back, which matches my theory. The prints were fine in the X axis, with an even layer.

So, after that long-winded explanation, I would like to know how others have set up the bowden tube and wiring so that it doesn't influence the effector. I have another IR sensor board on the way, so I'd like to get this sorted!

I use spiral wrap too, but it is a thin clear polythene type and it doesn't seem to make the bowden tube too stiff. Even so, I may try leaving gaps between the turns to increase the flexibility. Now that I've switched to 24V electronics, I could use thinner wires for the heater, which should help with flexibility.

If you are using Duet electronics, you can now configure height error offsets at each of the bed probe points in the bed.g file, to compensate for effector tilt that you can't eliminate. The trigger height errors on my build due to effector tilt are as high as 0.3mm in some areas of the 300mm diameter bed. I still haven't worked out what is causing the tilt.

Dave

Think I may have an idea on that I have just measured the spacing of the rods on the Alloy effector and carriages the carriages are all 40mm wide but the effector is 39.6 mm any idea where you can get 0.2mm thick M3 washer's?

Got my IGUS KBRM-03 rod ends and they are very nice tho will have to shave the edges slighty at the effector ends so they don't foul each other but there is plenty of meat on them to allow for this and need to go down a size on the CF Tube 5mm od and 3 mm id

they are not the cheapest but they are very well made and assembled as they come there is absolutely no slop in them at all.

Doug

Quote
dc42
I still haven't worked out what is causing the tilt.

Perhaps you have the same problem, and haven't noticed?
(Only joking )

I should have said that I plan to get rid of that spiral wrap - or I might separate the bowden tube, and just wrap the wires. I suspect that it's a combination of the fairly stiff bowden tube together with the bundle of wires - one's reinforcing the other.

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David J

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dc42
I still haven't worked out what is causing the tilt.

Perhaps you have the same problem, and haven't noticed?
(Only joking )

I too found that the effector bearing spacing was 0.40mm less than the carriage spacing - see my blog entry. I added one 0.55mm M3 washer per pair of effector bearings, so now the error is only 0.15mm. In any case, the error is not symmetrical about the centre of the bed, it's much worse on one particular side.

Maybe I'll swap pairs of rods around, and see if the errors move with them..

Edited 1 time(s). Last edit at 08/24/2015 03:26PM by dc42.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

David,

I guess you're talking about your Kossel - it's a bit hard to 'add a washer' to a Cherry Pi...

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David J
I found that braided stuff to be more trouble that it's worth! It frays at the ends as soon as you touch it, and it's impossible to make changes to the wiring later on. Oh - and I had the trouble I described earlier with the braided stuff... .

I use a small piece of heatshrink tubing at each end which I have thread onto the braid immediately after cutting it to length. As soon as the Bowden and cables are through I warm it up to keep things neat. I usually drop an extra couple of cables in over and above what I need at build time for future use. You can also make use of the fact that most pairs of cables have a shared ground connection if you need an extra core or two later.

Quote
David J
I'm starting to pay attention to my Cherry Pi delta once more, with the aim of sorting the problems that bugged me previously.

The first one is to do with the 'umbilical cord' leading to the effector:


Originally I used one of dc42's IR sensors, but had problems with an uneven print. David had mentioned that having the sensor some way from the nozzle could lead to errors in some circumstances, so as an experiment I replaced it with a mechanical switch activated when the nozzle touched the print bed. This worked better - but, following some different problems with the mechanical switch, I don't think that there was anything wrong with the original IR sensor setup.

What's happening at the moment is that when the effector moves to the front, the tension/stiffness in the umbilical cord is pulling on the hot-end platform and operating the limit switch. This means that I have to use greater spring tension on the Z-limit switch than I would like. With the IR sensor, I suspect that the umbilical was pulling the effector at the front of the bed and pushing when it was at the back, leading to false readings in the Y axis - and I was getting prints that were fat at the front and thin at the back, which matches my theory. The prints were fine in the X axis, with an even layer.

So, after that long-winded explanation, I would like to know how others have set up the bowden tube and wiring so that it doesn't influence the effector. I have another IR sensor board on the way, so I'd like to get this sorted!

I made my wiring/bowden/etc too long so I found mine was affecting my head too. What I did was attach a cable tie around half way (just a small one), then loop some elastic band between that and the opposing towers. Since the wiring was entering the build area between the X and Z towers, I looped it up around the Y and Z towers. Because it didn't seem to have much effect when the effector was near the build plate, I tied it up so there was no expansion of the elastic when it was basically on the build plate.

If anything this kind of solution meant that there was consistent strain as the elastic is only used when the effector raises. Not that there's a whole lot of effort being put in by the elastic, but it's enough to reduce the issues presented by having too much weight in the cable/bowden feed combo.

Not sure if that'll help you at all, but it might be worth looking into since it's cheap and potentially already lying around.

Quote
dougal1957
............

Think I may have an idea on that I have just measured the spacing of the rods on the Alloy effector and carriages the carriages are all 40mm wide but the effector is 39.6 mm any idea where you can get 0.2mm thick M3 washer's?
.............
Doug

Paper usual works well for a shims if you can keep it away from nuts and bolts that rotate when you tighten them.

Quote
SlowFoot

Quote
dougal1957
............

Think I may have an idea on that I have just measured the spacing of the rods on the Alloy effector and carriages the carriages are all 40mm wide but the effector is 39.6 mm any idea where you can get 0.2mm thick M3 washer's?
.............
Doug

Paper usual works well for a shims if you can keep it away from nuts and bolts that rotate when you tighten them.

Actually I have found some ready made shims from the RC Car world that will do the job nicely

3 mm shim set 0.1/0.2/0.3 mm thick

Doug

Hi,
Just started using my Pi and getting some very good results on thinwall prints for which I bought it. However on prints lasting over 30mins or so Im getting material leakage from the hot end plate which holds the heater and thermo (between this plate and the ally finned coolig tube) this results in degraded material falling onto the print. Is there a seal between this plate and the ally bit or does it just need cleaning?

Steve.

Steve,

I purchased a E3D-v6 hotend recently for my Cherry Pi and in the documentation it suggests that you tighten the heater block after you have heated the head to stop leaks :-

"When the HotEnd is at tempereature, tighten the nozzle whilst holding the heater block with a spanner. This will tighten the nozzle against the HeatBreak and ensure that your HotEnd does not leak. You want to aim for 3Nm of torque on the hot nozzle - this is about as much pressure as you can apply with one finger on a small spanner. The nozzle does not need to be torqued down incredibly tightly to form a good seal, when at lower tempreatures the aluminium will contract and hold the Nozzle and HeatBreak together."

Before having an original E3D I had a clone and I am so happy I upgraded to the E3D.

Matt

Thanks Matt,

Will do that now.

Steve.

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Matt,Wheatley
Steve,

I purchased a E3D-v6 hotend recently for my Cherry Pi and in the documentation it suggests that you tighten the heater block after you have heated the head to stop leaks :-

"When the HotEnd is at tempereature, tighten the nozzle whilst holding the heater block with a spanner. This will tighten the nozzle against the HeatBreak and ensure that your HotEnd does not leak. You want to aim for 3Nm of torque on the hot nozzle - this is about as much pressure as you can apply with one finger on a small spanner. The nozzle does not need to be torqued down incredibly tightly to form a good seal, when at lower tempreatures the aluminium will contract and hold the Nozzle and HeatBreak together."

Before having an original E3D I had a clone and I am so happy I upgraded to the E3D.

Matt

I can second that (although my Clone is actually a good one)

Doug

The clone hotends do leak sometimes. Plumbers PTFE tape around the threaded components usually stops it too.

Hi Andy,

Do you use support material to print the bottom stepper base? I see there's a part in the the design where there's a 90 degree overhang at the inside where the profiles are sitting.

Thanks in advance,

Hi Nilez

No. No support. It always seem to print ok bar a few strands that are easily removed

Andy

Hi,

I may be being a bit thick here but Im fairly new to this 3D printing malarkey so bear with me.

Im currently running Cura 14-07. My question is can I use the platform leveling wizard in the program to calibrate my printer, also do the latest versions of Cura support Delta style printers.

As I say sorry if Im being a bit thick but I do have a mental block regarding calibrating the printer Mutterings of M666 commands are a bit Blakes 7 to me!

Thanks,

Steve

Success at last!

Up until now I've been struggling with my Cherry Pi delta - I've had all sorts of issues resulting in uneven prints that were thick on one side and thin on the other, blobby prints, a hot-end that kept clogging and an extruder that would either chew up the filament or spit its end of the bowden tube out. All the sorts of issues that are fiddly to fix, and I'd got to the point of considering abandoning the delta for some other form of printer, such as the Core XY. I also had issues with getting my new Duet board and IR Z sensor to work - although they were almost certainly caused by mis-operation, they were frustrating!

After fiddling/fixing/replacing stuff such as:

• Making sure that the rods were EXACTLY the same length (now all within 0.001" of each other - sorry, my big vernier doesn't do metric).
• Making dc42's IR sensor mount for the effector.
• Amending said sensor mount to suit my own foibles and needs!
• Remaking the entire effector to a design by Maso (with modifications, plus additions designed by myself).
• Removing the spiral wrap from the bowden tube and wiring going to the effector - the wrap was too stiff and was influencing the effector.
• Trying a direct-drive extruder, then deciding that Andy's original Wades-style one worked better.

This evening, as a result of all this fiddling, I managed several very reasonable prints, including this one of the Escher lizard (which came as a test file with dc42's firmware).


This leaves me with just a few jobs to do, so that it can become a fully working printer - a print cooling fan for the effector, and better springs on the extruder - the current ones are too feeble.

Apart from that - I have much better feelings towards this little beast!

Congratulations @David_J!

I still fully love my Pi, and have used it to print another Pi for a friend. It's hard to believe that it's over a year old!

A question: I've picked up a Duet board but have yet to integrate it. Sounds like you're running one, so I was wondering if you've done anything to mount it?

I remember seeing that dc42 couldn't fit it under his kossel mini but I'm thinking there might be room under the Pi.