My Deltex || A Large-ish Format Delta Printer || Build log
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March 2020 - A Deltex V2 Arises
While the Deltex V1 served me very well, there were a couple of things that were kind of bothering me.
The first and most important of which, optimal use of rail length. Even at Z0 and at the bed edge, the linear rail sliders were still about 10-15cm from reaching the end of the rail, which is wasted height of course. Also, my existing rails were sourced oversees, while far for from the cheapest and decent quality, there were some spots that the block ran less smooth on. Combined with the fact that the rails are just a tad over 12mm wide and the tslot channels in my extrusions are just a tad under 12mm wide, alignment was always a bit wonky.
A second issue is belt tension. The bearings in the motors I had were not capable of supporting the tangential loads on the stepper shaft caused by the belt tensions I wanted.
On a similar topic, the last big thing I wanted to change was the motors. Similar to the linear rails, they were sourced oversees and were working fine, but quality and specs were a questionmark.
April/May 2020 - Proper delta endstops
As a part of the big V2 update, I decided I wanted to upgrade the endstops to something better then a run of the mill microswitch. In short, I ended up getting a set of Metrol STE060PB's. I have not performed any measurements but they feel and look absolute quality.
https://forum.duet3d.com/topic/15802/delta-proper-endstop-upgrade-advice
April-July 2020 - Alternative Belt And Motor Mounting
The bearings in the nema 17 motors I had were not capable of supporting the tangential loads on the stepper shaft caused by the belt tensions I wanted. After some nice discussions I ended up designing a mount that holds 2nd shaft. That shaft is supported by two needle bearing belts on either side of the belt pulley and connects to the stepper with a 8 to 8mm rigid shaft coupling. This way the tangential loads are supported by the two relatively large bearings.
https://forum.duet3d.com/topic/14674/external-bearings-for-stepper-shaftsApril-July 2020 - Stepper Upgrades Once Again
The necessity of going to nema 23 steppers has been questioned and discussed about quite a bit. I don't think there is a universally agreed answer, yet I opted to go the nema 23 route. After comparing quite a few high power models (within the Duet's specs ofc), I ended up getting a set of real nice PKP266MD28B's. They look and feel nice quality, offer impressive torque and are quiet by themselves.
https://forum.duet3d.com/topic/15860/delta-stepper-upgrade-advice-welcomeApril-July 2020 - Main rail upgrade
Even at Z0 and at the bed edge, the linear rail sliders were still about 10-15cm from reaching the end of the rail, which is wasted height of course. Also, my existing rails were sourced oversees, while far for from the cheapest and decent quality, there were some spots that the block ran less smooth on. Combined with the fact that the rails are just a tad over 12mm wide and the tslot channels in my extrusions are just a tad under 12mm wide, alignment was always a bit wonky.
I decided to get proper brand name rails that are at least wide enough to cover the 12mm of the frame gap comfortably. The set of THK-SRS-12WM's I got are 40mm wide and 1030mm long. For sure overkill in terms of load capabilities, but boy are they nice. They also feature caged balls inside the sliders, making them very quiet and easy to install. The balls don't go all spring sproing when you try to slide a block on the edge of a rail after cleaning for example, which is surprisingly nice. The specific set I got are coated black (no idea if it is anodized or what process they used), thus preventing surface rust.
###July - December 2020 - The noise
With the upgrade to the Oriental' nema 23 steppersa new problem arrose. Resonances in the frame caused absolute terrible noises that could be heard at hindering levels around the whole house. Over the course of several thread and over 200 posts a have experimented with several successfull and less successfull solutions to combat these vibrations. In this section I will try to summerize these post into something more digestible
This whole process started with the vertical extrusions resonating. They were vibrating enough the clearly feel it when I put my hand on them. Over in the first thread, a user suggested bolting something heavy to the towers and quickly concrete became the product of choice. I poured some concrete (with blue die
) slabs and bolted them to the towers. The added mass (~30kg each) did what it was supposed too and silenced the towers.
Sadly the noise issue was not resolved at all, just reduced from loud enough that the neighbours could complain to loud enough that people in the same house complain. At this point I looked into building an enclosure to reduce the noise levels outside of the machine. Here I considered to big options, one was to build a box and put the printer inside of it and the other was to integrate the enclosure and the printer into one enclosed system. I opted for the latter appoach and build 3 panels out of MDF, lined with sound dampening material, that would bolt to the towers. Altough they look quite nice, provide mouting options for a variety of things including watercooling and 4th axis rails, they do not serve their original purpose of sound isolation. I think the big mistake here is that the panels effectively provide more surfaces that can vibrate with the machine. And while the sound dampening material no doubt does its job, the vibrations couple straight into the wood and practicaly bypass all dampening.
Another thing I investigated is the motor mount. One issue that I found out was that the back of the motor not just vibrated in air but vibrated against the plate it is mounted on, causing even more noise. After ajusting the motor mount to give some clearance between the stepper and the frame that issue was resolved and quite noticeable.
A second change to the motor mount is the addition of flexible couplings on the axle. I did not really notice a change in noise levels but I needed something that allows for some minor misalignment between the stepper's axle and the axle that pullies sit on.
I also added the well know Astrosyn style face dampers between the motors and their brackets. This did improve the noise noticably.
Finally, I completed the bracket design to my desires and had them machined outof stainless (stainless is overkill but due to a deal it was the cheapest metal available at the time). They look absolutely awesome and clean in addition to a minor reduction is noise.
This is where this section on noise will be closed for a while. The noise levels are quite acceptable but not perfect. A number of options are still on the drawing board, such as different steppers and a closet style enclosure.
https://forum.duet3d.com/topic/17513/to-rigidify-or-not-to-rigidify-vibration-issues
https://forum.duet3d.com/topic/17725/building-a-sound-dampening-enclosure/
https://forum.duet3d.com/topic/14674/external-bearings-for-stepper-shafts
https://forum.duet3d.com/topic/18281/battling-sources-of-vibration-and-noise -
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Update: completed sections
July 2019 - Bed upgrade
January 2020 - Epoxy Granite Machine Base -
Update: finally got this post more or less updated to current time, enjoy the read
I am also pleased to announce a Deltex V2 which is just about confirmed to be coming. It will not be a 3rd printer as it will reuse the majority of the existing frame and other components. Some changes that are currently planned:
- Linear rail upgrade from Robotdigg MGN12's to original THK SRS series rails.
- Optimization of rail placement should increase build height ~10-20 cm.
- A sound and temperature insulation enclosure.
- The existing fourth axis with v-slot rail with be swapped for the old MGN12 rails. Furthermore, the 4th axis mounting points will be incorporated into the enclosure.
- Water cooling components might be moved to be stationary on the outside of the enclosure walls.
- New way of mounting the steppers/belt idlers to relieve stress from the stepper bearing at higher belt tensions.
- Existing printed corner brackets in the frame will be replaced by metal brackets.
- Possibly the introduction of even more metal parts as replacement for current plastics.
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Update: Finished writing the final piece of the Deltex V1 build log. Currently designs are being drawn and parts are on order for the V2, exiting time for sure.
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Updated again: added the section about the noise issues I have been having and some picture
