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Discussion in '3D printers' started by David Bunch, Sep 30, 2019.
Upgrade my 5 year old Makerfarm printer to use more V-Slot
David Bunch published a new build:
Read more about this build...
How were the prints BEFORE the upgrades?
The prints have not changed much from the upgrade. Think I did get rid of a little bit of the ringing in the prints. I also upgraded to a bigtreetech SKR V1.3 32bit board with TMC2208 on x & y & LV8729 on the Z & Extruder. The new front & back plates with the 2020 V-slot does make it a lot more sturdy & less vibration. I have some cork gaskets for the motors & will probably add one to the Y-axis motor first to see if that makes a difference.
I was looking at Makerfarm's option for upgrading the i3v to their Pegasus version which has the V-slot frame around it, but I don't really want to spend the $165 for the upgrade since I really only need the V-Slot parts which I already have. I took a look at their manual & saw an angled plastic part to connect the top V-slot to the angled V-slot support to the back like a number of machines of this similar design use. I had already sketched in 2D of doing this style support, so I started drawing this up in 2D, then put it in openscad with variables. Since I don't know what my angle will be for this, I made that variable along with some of the other widths. This connects a little different than the Pegasus & it will probably change. I was also looking at this neat V-Slot Hinge that openbuilds has. Adjustable V-Slot Hinge Here is a screen shot of that design. I need to put more of the V-slot together in openscad before printing as I might want to connect 90 degrees to what one of them is. Once I get it closer to what I want, I will put it in fusion 360 since I can smooth out the sharp edges a little easier. I have to get my Folgertech Kossel changed over to the 32bit board before I do anymore work on this.
Doesn't look like I need to add that angle bracket I showed in my previous message. I got my Kossel printer back up & running on new 32bit board, so I am getting back to this project. After Test fitting some V-Slot around the machine, think I came up with a solution with minimum changes to the design & no cutting of V-slot since 500mm fit nicely. I leave the Wood frame in place & build the frame around it. I have already added the top 2020x500mm & changed the front to a 2040x500mm. I had to raise the front belt idler tensioner up with one washer to clear the V-slot. I needed to change the back plate to use 240x250mm instead of the 2020 in order to get a 2020x500mm connected behind that, so I changed the wood connection parts & will have to use single plastic connectors for 2020 V-Slot that the Y-bed rides on. I could use standard metal corner brackets for all the V-Slot connections, but I do not have enough, so I will design some plastic one & see if that is enough to make this machine more rigid. I pieced all the parts together in fusion 360 before printing any parts to see if I missed something. Looks like it should work. The 2060 for the verticals is probably overkill, but I am using the V-Slot I have on hand. Here is a screen shot.
While waiting on some prints I designed this specialized corner part that will go between the Front & Side bottoms. I will only use one of the M5 end holes. Not sure there is enough clearance for both screws. Fusion 360 makes this easy. I can put a design together a lot faster with this software rather than my previous workflow of Draftsight for 2D & openscad for final 3D. I still use the latter 2 softwares for some things.
Here is another cute corner I made for the back. My printer jammed on printing my 2nd wood connector on the back, so I have to fix that before I can print again or I might try printing them on my Delta. This connector requires 2 t-nuts & one screw is threaded into end of v-slot.
I cleared my extruder jam which wasn't too bad. I printed one of the smaller corners to test before printing a 2 hour print. The backplate (1st image) that connects the 2 y-axis V-slot that the build plate rides on I was going to make separate parts since I changed this V-Slot from a single 2020 to a 2040,2020 combo, but it does make it a lot easier to put together with both sides connected. This morning I came up with an idea to keep it one part & also make it the connection plate between the 2040x250mm & the 2020x500m V-slot. Looks like that will be a 3 hour print. I will print it on the angled side so it requires no support. Using this to connect to the 2020x500mm also saves me 2 screws & t-nuts since I was going to use a simple joining plate to connect these 2 V-Slots. I count 26 T-nuts for this upgrade. Think I have all the parts for my upgrade into Fusion 360. I discovered one problem when putting the parts in the assembly & that was the P/S side Wood connector was going to interfere with the new Backplate connector. I could have shifted the back 2040x250mm a little more towards that bracket, but that would have made the other side a longer reach. I ended up cutting a little recess cave for that part to slide in. This looks like it should not affect the strength of that connection. You can see this recess in the 1st image. I also updated the build icon the 2nd attached image. This upgrade currently uses the following V-Slot:
1-2040x250mm Y-axis Back
4-2020x500mm Far Back, Bottom Sides & Top
2-2060x500mm Vertical Sides
I was playing with making the corner parts more parametric in fusion 360 using more variables & tying down the dimensions. I added the fusion 360 file for this, in the files area as Corner_60mm v2.f3d along with Corner_30mm.stl, Corner_60mm.stl & Corner_30mm.stl files in case someone wants to play with this design some. If you change any of the variables & making it shorter than 43mm Len or Ht you should change the Side_Rad & Side_Offset first to keep the geometry from going wacky. This files uses 2 holes, but if you want to use just 1 or add another, just change it in the 2 affected sketches & extrude them again along the timeline history. The other variables to change as I mentioned in previous sentence are Len & Ht. The Ht variable I have set to Len, but that can be changed to a different dimension if desired. The Thk variable is the thickness of plastic where M5 screw goes thru. M5 variable is diameter of M5 screw Hole & there are a few other miscellaneous variables you can play around with. The 30mm plastic corner I printed seems like it should suit my needs, but I may try the other sizes later. Here are 3 images that show those 3 sizes compared to the black angle metal corner which you can buy. I test fit 2-30mm corners on & it feels pretty sturdy after tightening screws all the way down.
While test fitting one side, a 2020 base & 2060 vertical on the side I noticed a potential interference problem with the X-axis motor assembly or it will be a very small clearance. After placing that same part on the other side to look for problems there, looks like I can just shift the frame more towards the x-motor side since I have plenty of clearance on that side & there is nothing tied to that frame that won't let me shift it that way.
The more I look at this design, the more I find something I can change. Looking at what is still connected to the wood, it is only the motor mounts & the 2- 2020 Z-axis V-Slot. I was looking at how to connect those to the side vertical 2060x500mm V-slot & realized it is 500mm across the width of that middle section to connect to both 2060. The only problem I just noticed is the y-axis 2020's are only 30.7mm above the bottom frame. I wanted to use a 2040 across there, but 2020 would work. I could make the y-axis end connectors higher up to clear that & be able to use 2040, but using the 2020 sounds simpler & probably more stable. I will think about that after completing my current upgrade version. I could still use the 2040 or any other 20xx, but lay it down so the 20mm is the height.
I got it all put together today & it feels a lot more sturdy. It fits well & test cube print has less ringing in it. The only part that does not fit well were the front corners & I thought might be a problem. It is about 17mm extra space. I will just design a corner to fit the space later. It is only a cosmetic issue for now. Here are some photos. I needed 2 more T-nuts so I used a couple of drop in T-nuts that I had. You can never have enough T-Nuts. I shifted the frame 15mm towards the X motor from my original dimensions & I have exactly 15mm clearance on that motor. All & all I am happy with this upgrade. I started working on a Z motor mount in order to get rid of wood all together, but will leave it alone for now. I could probably print higher now by changing the 400mm lead screws & 2020 verticals to 500mm, but I very seldom wish I could print taller. I do sometimes wish I had a 12" print bed.
Now that I have the external frame pretty much the way I want, I am looking at other things to improve on this printer. I have been having some extruder issues, so I started working on designing a X-carriage with the pancake motor mounted against the plate as I have seen other designs do. This will allow me to change it from a Titan to a BMG to see if that is better. I have a drag chain currently connected to the front of the extruder & snaking out along the Y-axis. At the time that was the easiest way to do it without redoing the X-carriage. Now that I am redoing this. I am connecting it to the top. I connected all the affected parts into the fusion 360 assembly, so looks like it should work. I initially had the drag chain centered on the 2020 top X-axis, but moved it 2mm in to give a little more clearance on the M8 Lead screw. I am using the openbuilds 500mm length drag chain for this. Here are 2 screen shots of what the design currently looks like. One from the Front & one from the Back.
I ordered that book that openbuilds mentioned recently, "Designing 3D Printers" & it should be here today. The price dropped a little over $9 for that book since I looked at it a week or so ago. Thanks openbuilds for pointing out this book.