I received the Wham Bam System the other day. Before it came, I had watch of the youtube video here and a read over the instructions on the website.
One of the recommendations is to remove the glass bed or build surface that is currently installed to the printer. I can understand the logic in this, as surfaces like glass aren’t very good conductors of heat. Therefore, to install another build platform on top would reduce the effectiveness of the heated bed.
After mulling it over, I decided that the heated bed had to come off. To achieve this, you need to heat it up to at least 90 degrees Celsius. The adhesive holding it down is then soft enough for you to be able to use a combination of spatulas and flat bladed screw drivers to gently prize it off.
What remains is a very thin heated bed. During the removal of the ultrabase, it is virtually impossible to not bend or misshape it. You could try and bend it back into shape, but the first knock or fast probe would bend it out of shape all over again.
I took the decision to bond a 4mm aluminium plate to the top of the bed. I got the plate laser cut by a nearby company who have done work for me in the past, but any laser cutting company who deal with aluminium should be able to do it for you. There is a company on ebay in the UK who will laser cut a 380mm piece of 4mm aluminium for £29 (including postage). I used JB Weld to attach the heated bed to the aluminium with great success.
Following the instructions, I then installed the heated bed.
I then installed the bed to my printer.
I’ve done a bit of printing with it so far, but I’m still tweaking my cura profile to match it. One thing to remember when printing PLA is that you need to halve your standard first layer. My first layer is now 0.1mm but I’ve still seen a little bit of lift (I am not using a brim anymore). Another note as well, I was also seeing temperatures on the build plate 5 degrees lower than what was being reported by the printer (maybe due to not soaking the aluminium plate long enough, I don’t know), but I now print with a heat bed temperature of 75 degrees. Wham Bam state you should print with a temperature 10 degrees higher than you did before.
My mesh height map is not fantastic, but I am hoping that the duet will deal with that.
I’ll add another post about using the Wham Bam Flexible System once I’ve done some more printing.
Just a short post to say that I have now received the Wham Bam System and I am already itching to get it installed.
A couple of things to note. I had to pay import duty of £37.58 (which included £12 processing fee). Bit of a bummer but was expected.
Secondly, I am currently trying to decide how I want to mount this. My options are mount directly on top of the ultrabase glass, mount directly to the heated bed (which is super thin) or remove the glass, mount an aluminium disc to the heated bed and then mount the Wham Bam system to this.
If anyone has any thoughts on this, that would be great!
As quick as that I am back to the original 1.8 motors. I now remember why I never used the ones I posted about.
They are 2.4 amp motors and I had them running at 1.8 amp and they were still skipping steps. I think I’ll get some 0.9 at some point, just need to research the best model. Didn’t take long to swap them back.
Since I last wrote a blog post, I have carried out several changes to my current setup. The aim of this post is to try and consolidate all of the changes I have made to try and put a stick in the ground for the readers.
Summary of changes so far
The controller board has been changed to a duet 2 Ethernet. This has been detailed here and here. As well as this, I have changed the effector to a smart effector. This change also meant changing the hot end from the standard v5 clone to an authentic E3D v6. These changes were detailed here.
My setup summarised above was using the original arms that came with the machine. If you follow the Facebook group for the predator, or any other social media channels, you may have heard about the issue of the rapidly wearing rod/arm connectors. This is where the ball in the middle of the connector becomes loose and introduces play into the system. I was suffering from this issue, and it meant that the calibration deviation on my machine was getting worse and worse. One fix for this issue suggested by the community is to replace the rod connectors with ones made by IGUS. These would be great for a normal unmodified machine, but as we’ve already fitted a smart effector, these aren’t really the way to go. It would also be very difficult to make sure that the rods are the same length. This is critical to ensure that the printed parts are accurate, especially as resolution decreases the larger the part.
I ordered a set of arms from Haydn Huntley. He has been known for supplying high quality, high precision arms to the delta community for several years now. I decided to stick to a length of 440mm for the arms, although it has been suggested that arms as short as 405mm will still work. The reduction in length to 405mm will counter the loss in height when fitting a smart effector (which is around 30mm due to the different position of the hot end). I’m not going to tell you which length to order as I have not read anywhere of anyone ordering 405mm and getting them to work over the whole print area. If you feel you will need that extra z height, maybe go for 415 or 420mm. If you are planning to use any sort of multi material changer at some point in the future and will be planning to purge the material outside of the build platform, then I would stick to 440mm arms. The order came within about 2 weeks or so. Just keep in mind that when getting them delivered to the UK that you would be paying somewhere in the region of £30 import duty. They come well packaged, in a cardboard tube and have the length of each arm written on a label. All the ones I received were 440.38mm.
To enable the arms to be mounted to the carriages of the predator, some custom mounts are required. It would be great if the adaptors included with the smart effector fit, but unfortunately, they don’t. I used the adaptors designed by Nealz Engeland but I found that some modification was required to get the holes to line up with the carriage. Don’t forget to swap the little ‘flag’ over required to activate the optical end stops.
I carried out this change while also carrying out some maintenance on my machine. One of the good design factors of the predator is the ability to remove an upright from the machine without much hassle. The predator even stays in place without requiring any other support. I removed each upright in turn and stripped it down to parts. This way, I was able to check that all the rollers of the carriage were correctly in contact with the extrusions and that no play was present. Fortunately for me, there was no play present, but I have read on Facebook, about a number of other predator owners that have had to adjust their rollers to make sure they are all in contact. I also swapped the original 1.8 degree motors with 0.9 degree motors and re-tensioned the belts, but more on that later.
As mentioned earlier, I have previously upgraded the effector from the original to a smart effector. I had modelled up a mount to allow use of the original arms and to mount three radial fans for cooling. The design can be found here.
I have since updated this design to allow the fans to be mounted to the smart effector while using magball arms instead. The design can be found here.
When mounting the arms to the printer, make sure you alternate the polarisation of the magnets. With mine, Haydn fixed the labels on each on at the same polarisation, which made it easier to alternate the arms. Basically, mount one arm label in to the effector, then one arm label to the carriage and then alternate. This helps reduce magnetic interference of the fans etc. Also make sure that you apply lubricant to each of the ball cups. I used bike chain lubricant as per Haydn’s advice.
The motors are very easy to change from one type to another. I had a bunch of motors left over from then I had to send a 3D printer to 3D printer heaven. The main thing to check is that the toothed gear is fitted with the same offset as the gear at the bottom of the printer. Wiring is the same as a 1.8 degree motor. If you’re lucky, you’ll get 0.9 degree motors with removeable cables, in which case, you just plug the old cable into the new motor. Don’t forget that the steps per mm need to be changed from 80 (for 1/16 microstepping) to 160. I’m still assessing whether changing the motors has been a good change or not.
Only a small note to say I’ve added a PanelDue 7 inch. I have mounted it to the top of the frame as shown below.
Duet firmware updates
Along with the above hardware changes, I have been trying to tweak my duet config to improve my settings. I have uploaded my current config to a separate branch on my github for your use. You will notice that the acceleration and jerk are quite high. Below are a couple of pictures of an example part. Ignore the bottom of the part, I am currently working to improve the quality. I will endeavour to keep github up to date.
I have moved a couple of items out of config and into my start gcode. I now do the following.
G32 ;This carries out a delta calibration at the start of the print G29 S2 ;This reloads the mesh height map which is cleared when carrying out the delta calibration.
I had converted my predator to a BMG clone (a fysing one) fairly soon after getting it, after using one on my linear plus. I had purchased the same brand based on the assumption that if the first one works well, why shouldn’t this one. But on receipt, I noticed that the plastic gear fitted to the main shaft wasn’t mounted perfectly concentric. I fitted it anyway and for a few weeks it worked as expected.
I then noticed a piece of plastic had fallen off, and on further inspection, it was the plastic holding in the little bearing on the main body. This missing piece of plastic resulted in a reduction in the amount of pressure that could be applied to the plastic when extruding. After super gluing it back in place, to enable printing to continue, I decided that I should be looking for alternative brand.
That’s when I came across the Sanjiu all metal BMG clone extruder on aliexpress. The main difference between this and other BMG clones is that the whole body is made of machined aluminium rather than being injection moulded plastic. There are even threaded holes to allow you to mount a fan if using it as the heatsink of the hot end (although working with a delta, this isn’t an option). So I took a punt and ordered one.
When I received the extruder, I stripped it down as far as I could and took pictures of all the components. Everything is made from metal (apart from the roller bearing cages for the one gear). It all assembles really easily and is obviously well made. The main difference between this extruder and a plastic equivalent is the weight. This weighs 68g compared to 131g of a clone. We all know that weight can make a difference but I believe the better rigidity of a metal extruder outweighs the cons of added weight.
I have since fitted it to my machine and I haven’t had any issues with skipped steps. Only time will tell if it works well or not. I shall give an update on it soon.