I found that just relying on the clamps on the top pulley mounts to keep my belts tight was not all that great. For starers you need four hands to apply tension and tighten the nuts and bolts and its hard to fine tune. Also these are smooth rods so overtime the top could slip down.Since 3/8" threaded rods are real cheap, I added two at the back corners and one on each side towards the front. Now I can just turn a nut and get the belts as tight as I want.
As this was not in my initial design I had to as small metal plates that I just had lying around to get the rods at the front clear of the movement. If I was doing this from scratch I would change the shape of the top and bottom pieces so the angled out a little towards the front to cater for the rods.
These rods could also be used to attach angled brackets if I want to add more rigidity to the frame.
My next mod will be the relocation of the Extruder. I worked out by suspending it below the top plate about 19cm below the top. It will sit right above the head just clear of the home position and shorten the Bowden tube by almost 50%. Is an easy mod I will try it during the week. I am hoping that shortening the Bowden will improve its response after a retract.
Great Idea! Now, I just thought if on each rod you capture a wing nut tightly between two regular nuts you can loosen the rod screws and twist a wing nut to tighten and - Bob's Your Uncle.
ReplyDeleteI thought about wing nuts, but just having the threaded rods there means I will not need to retention it so often anyway. At both the top and the bottom there is a nut above and below so you can lock it pretty tight. Its an inexpensive mod costing only about $15.00. And also later if necessaty they can be used to hold angle brackets if I feel it needs a few diagonal rods to improve stability.
DeleteWith your shorter tube mod, it sounds like it will also be straightened? I bet that will help responsiveness as well. Do you have any other prints to show off? I'm interested in seeing how the quality stacks up.
ReplyDeleteMy heat resister in the hot end has blown so I am out of action until my new ones arrive along the heat goo. They have been despatched so I expect a couple of days.
DeleteThe reason I am shortenning the tube is to increase the response but Bowden is a new area for me so I am not sure how much differece it will make. During my last tests before the hot end went out of action. I had retractions working perfectly but the restart after a retraction did not start depositing immediately especially where the hot end had to deposit a small bits here and there. Thats what I want to improve
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DeleteHi bill!
ReplyDeleteWould you be able to comment on whether or not you had problems fitting your plastic parts into the build? (Did your plastic carriage fit the linear bearings flush, and did the jaws fit the joints no problem? Or did you have to do some sanding?)
Please see my pics:
https://groups.google.com/forum/m/?fromgroups#!topic/deltabot/32EW6wDq6TE
Thanks bill! :-)
Hi Arnold,
DeleteI did not really have any issues. I had spent quite a bit of time tuning my existing printer to ensure that printed parts fit as expected. I only really had to file off some burrs here and there and drill out the holes to clean them up a little. Everything was a fairly tight fit but they all fit pretty well.
Thanks Bill!
ReplyDeleteNow you have been printing and motion. Could the threaded rods, used for belt adjustment, be three and placed just forward of the motor mounts and between the rods?
ReplyDeleteMine is not assembled yet so, I can't visualize. It seems there may be a small column of dead space forward of the carriage, motor mount, and between the rods?
I just noticed that you do not need the top most nuts. The threaded rods are captured and under stress. Wow, you don't need the bottom most nuts either. You have created an expander which keeps your belts tensioned and the belts keep pressure on your threaded rods which, can not come out. So, you only need the interior nuts. Then, I now realize, it is just a few twists of the inside nut to create more tension. Very Good. Now, just about my previous query regarding moving the threaded rods to a dead space between the carriage, motor mount and rods???
ReplyDeleteThe topmost nuts I can prolly do without but the bottom ones lock the rod and stop the rod from turning as I try to tighten or loosen the nuts under the top.
DeleteIn regards to placement, they wont fit where you descrobed as they will hit parts of the carriage as it moves to the stops because the carriage is a triangle. Also by placing them where I have it makes it easier to add diagonals if I want to increase the rigidity of the structure al though I am finding ay the moment there is very little shaking from this design compared to a traditional one which can shake the whole desk.
BTW they are changing the firmware soo so that we do not need the bottom sensors. I am not sure how that will work but will wait and see.
Does your printer have a column of clear space just in front of the carriage and between the printing rods as the printer moves?
ReplyDeleteHi BAS... I think I know what you mean. There is a small amount of space at each apex of the carriage where the level adjustment screws drop down
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