Having recently said goodbye to the Anet A8 I needed another machine to complement the other two printers, Creality CR-10 & Geeetech i3 Pro B, remaining in the print farm. My intension has always been to run with a minimum of three machines simultaneously at any given time and with the sale of the mighty Anet meant I was one unit short of what I needed as part of my self-imposed minimum operational requirements.
But why three? The reasoning falls into line with my personal engineering philosophy, that being – Three is two, two is one and one is none. At this point the cluey ones among you are probably pointing out that the saying actually goes “two is one and one is none” Where does this three is two business come from? Well here’s where, I adapted the three is two attitude a while ago after hearing about it from an ex-navy electronic engineer describe the practise giving an example of generators on an army base. It basically goes along these lines: If there are three machines operational one can be taken out of service, say for scheduled maintenance, and there are still two machines operational with one backing up the other should anything go wrong. My planning includes the assumption I will always be working on at least one of the printers at any given moment or alternatively there will always be an issue needing attention on at least one of them.
It is not a safe place to be having sold one of the printers and being down to only two when there is a business relying on there being a constant output and leaves the production schedule vulnerable to unforeseen problems. The solution is easy enough, get another 3D printer to make up the numbers which in itself presents a fork in the road for how to best action the solution. Buy brand new, which is obviously the more expensive route to take and given the current global situation with COVID it could take weeks if not months before expected delivery to my part of the world. The main advantage would be its a brand-new machine with nothing to fix. It’s simply a case of put it together, change a few settings, feed it a gcode and away it goes. It is definitely the easier option and as expected there is a price for this convenience. Or there is the alternative option turn to the classifieds to find a decent used printer. This is definitely the cheaper of the two options but there are risks with this as well, it may (also) take weeks to find something decent and worth buying, and then who knows what issues might be lurking waiting to be uncovered and what could end up costing to fix in terms of time and money. As I feel confident enough knowing what I am doing, and because I am a huge tight-ass I chose the latter option.
The third printer was needed to be up and running quicky to ensure that I can put in motion my rule of threes. It is especially important as I have printing demands which are growing and that I need to ensure I have production capacity as soon as possible. So after a short period of time looking around the local classifieds I managed to snag a preloved Tevo Tarantula off gumtree for a reasonable price and from a seller who seemed to know a thing or two about 3D printers. With the Anet sold less than a week prior, money made from that sale was put directly towards purchase of the Tevo, as a result I thankfully didn’t outlay a huge amount of cash to buy it. As the seller was moving overseas and not being able to take it with, this meant spare parts and a few rolls of filament were thrown into the deal as well (Woohoo!).
I remember when I was looking for my first 3D printer I had considered a Tarantula as a serious contender. After reading many reviews about how truly shit they actually were, none more so than this one from All3DP where it scored a whooping one and a half stars out of five, I ended up with a CR-10 as my first printer and let the Tarantula go as not being a good enough option. The only reason I considered buying one again was because of the fact they are now so cheap and this one in particular had upgraded parts on it which I assumed would resolve all the issues which were present on a standard machine.
As mentioned, this particular Tarantula caught my eye as it isn’t standard and features some tasty mods including: Upgraded aluminium frame braces; BL touch auto bed leveling; dual Z axis motors; E3D (Clone) Volcano hotend; Upgrade solid state relay for heat bed; and a complete Ikea Lark enclosure setup, which I may or may not end up using given my current lack of space available for anymore 3D printer stuff. In this instance it worked out better buying used and getting all these goodies thrown in. To do all this level of modifications from scratch with a brand new out of the box 3D printer would have ended up costing much more than what I ended up paying.
In reality, first impressions of the Tarantula are pretty ‘meh’ to say the least, not bad but not good. Even with all of the additions and modifications there is still much room for improvement. The print quality is seeming fine, not to CR-10 levels of smoothness or accuracy but close. There is some issues with stringing which needs to be addressed, all of which will come in time as the machine is dialed in and correlated to the filament, working better together for the best results.
One thing I can honestly not believe is how poorly designed the Tarantula is. It is made up of decent quality components – Aluminium extrusion frame, MKS control board, clone titan extruder but all this doesn’t overcome the fact its fundamentally flawed in its design especially the design of the frame. This is a first-generation tarantula which has since been replace by a newer model featuring a frame closer to that of an ender 3. This first gen frame really is a wobbly and convoluted thing even with the addition of aluminium corner reinforcements it’s still not enough to save this printer from itself, the corner reinforcements do help but just not enough and there is still plenty of movement in the Z axis of the frame. Tevo have obviously tried to strike a balance between keeping cost down while still giving some quality hardware as part of their kit, unfortunately the design direction they have gone with was probably the wrong one, focus should have been of a design philosophy which is proven and well sorted instead of trying to work around the problems by adding better components. For example, my Geeetech i3 pro B is pretty average in terms of its build quality and components used but because it is based very heavily on a Prusa i3 which has a tried and tested design, it will print consistently all day every day and won’t shake itself to bits in the process which is something I’ve had to be dealing with on the tarantula. The Z screws acting on the X gantry is specifically what I am talking about in this instance.
As mentioned this Tevo features upgraded aluminium corner reinforcements which I’d consider an essential upgrade, the standard plastic corner joints are flimsy, cheap and nasty in comparison. Even with these aluminium parts, the frame is still has wobble but is an improvement non the less. I’d would hate to think of what this thing would be like without the aluminium beefing up the frame.
Another essential upgrade is dual Z stepper motors which is a must not just for this printer but for any machine which only has a single motor as standard. Tarantulas come from the factory with only a single Z axis screw on the right hand side of the frame, while I don’t have any before and afters comparison to draw against for I can look to my CR-10 which went through a similar upgrade of going from a single screw to dual screws, with reliability and print quality improving by a marginal amount. One thing I changed almost immediately on the Tevo was the Z axis ‘upgrade’ of Oldham couplers – These things are garbage! In the few prints I did in the first fortnight there were numerous occasions where the lead screw nut would unwind itself off the end of the coupler and end up at the bottom of the threaded rod. I have never ever had this kind of issue before on any of my other printers, so I removed these useless parts and replaced them with an aluminium version of the stock X gantry tab. So far not a single repeat issue I’m happy to say!
One more point of note is the MKS base 1.4 uses A4982 stepper drivers which are pretty noisy, about on par with A4988. I will put up with the noise produced for now but its something to consider changing them out in the future for some quieter drivers such as TMC 2208’s. But as the stepper drivers are soldered into place and cannot be removed, this would also require the control board to be changed. It could be an opportunity to upgrade the board with a MKS gen L or even a Duet but as everything is still working I doubt this will be happening any time soon.
Remember how I mentioned that sometimes its better to buy used? Skip forward to two weeks of ownership of this printer, and now I am faced with the cost of replacing a faulty BL touch which has decided it won’t deploy anymore. This is obviously a risk which needs to be taken into account when buying anything but even more so when purchasing used electronics. Even brand new from the factory things go wrong, don’t work or fail but with a used printer this likelihood is so much greater. For the Tarantula this is just one of those unfortunate things, a BL touch is easy enough to replace but the machine will have had to sit for days while the new part arrives in the post. This should lend itself to a good lesson in keeping spare parts on hand especially if you (like myself) intend to use a 3D printer for more than just a hobby.
Despite all the wobbly bits and questionable design choices, from the hand full of prints I have completed there is potential but it’s something that will have to be worked on over time. At the present moment it just needs to be running reliably.
As I write this the Tevo sits idle waiting for replacement parts so it can function as it did once before. There is always wisdom to be drawn out of difficult and frustrating times and this it will be no exception for me. Maybe in this instance it would have just been the safest option to buy brand new. Of course there would have been the cost of a new 3D printer with those at the cheaper end of the scale being 50% on top of what I paid for the tarantula, the big advantage would have been none of this stuffing around trying to get a printer working by doing a technology rain dance and making sacrifices to the silicon gods. Ultimately this was a gamble I bet on and my horse tripped out of the gates, hopefully it will recover to finish strong.