Over in the shop we are running a preorder for the CNC conversion kit. Here we would like to give you a bit of background on how it all came about and our design intent.
From day 1 of ordering the EMV-25VBB milling machines, the CNC conversion kit was always going to be an option we would offer. As the development reaches commercialisation and release, let us give you a bit of background on how we designed and thought the project through.
The first conversion our team did involved a Chester Machine tools Super lux. At the time, we were short of cash and also wanted to get the machine running asap. This was not a good combination as corners were cut, money was skimped with the end result…well much to be desired. Thanks to that machine one of us learnt to hand scrape for flatness and alignment as well and owns more metrology tools than we would need, a Biax powerscraper and a granite table.
The following learning outcomes have stayed with us as we designed the conversion kit for the EMV-25VBB:
Servos are so much better but Steppers can be good
Granted there is a cost to servos and there is also a learning curve regarding PID position control and parameter tuning. Thankfully Clearpath servos are here to save the day! Plenty of YouTube videos to prove why, including John Sanders’ special projects! Thankfully for those with a limited budget, the option of using steppers is not eliminated due to the servo motors we will ultimately inlcude are also Nema 23 frame sizes. The added bonus of the servo is that you can back drive it much easier than a stepper. Our protoype kit sports steppers, because that is what we had at the time
Don’t touch the castings!
Invariably the castings used on the machines we are aiming this kit to are not aged or stress relieved. In some cases they are not even ground well enough. On our Chester we found that even drilling lubrication points was a bad idea as the saddles would move killing the accuracy we hand scraped into them. So great effort has been expended to get a custom made ballnut and ballscrew mount to allow fitment of the X-axis screw. In fact we even use the same screws from the factory in most case. No more hunting around for a mate with a Bridgeport!
Yes you read that right, no too ways about it. Yeah you can use the CNC controllers backlash compensation function but why not just eliminate it from the getgo? We came to this conclusion about 3 months after we put the first machine together. Kept chasing repeatability, squared off circles and steps in all directions. So ditch the silly ideas of springs between the nuts, shims etc and go with quality precision manufactured ballscrews and bearings throughout.
Hence our kit is based on C5 accuracy ground and preloaded ballscrews. They are so good they can be backdriven!
Wish I had kept the handles
Why code a a hole drilling program if you only want to do a quick job? Not going to eliminate the quill too right? So yeah, jogging with a keyboard is impractical and for the one quick hole you want to make using that drill you cannot really be bothered to touch off…Lets keep the handles on. Oh but wait, what happens when the handles are spinning with the motors? Best make them the safety kind.
In order to eliminate backlash and lost motion, we have made the ballnut mounts out of steel. As you may already know the coupling between the casting and the nut occurs through a boss and it is held in place with a single screw. Using steel we know that the parts will last a long time with no loss of rigidity.
What machines will this fit on?
The kit came about with some help from Aaron Powter of Youtube fame. He designed his kits to fit the Titan machine tools, available in Australia. His kit fits the AMAT25LV, the Optimum BF20, HBM BF25 and other machines too. The biggest difference between the EMV-25VBB and the other mills is the end of the table. Ours takes a small flange that does not cover the ends of the T-Slot area, while the others have a larger plate. To keep all of your covered we have designed both variants.
How do we get this kit?
Getting the numbers up is critical in being able to make this viable. Unlike the other kits available, we have put great effort to ensure it is as plug and play as possible, this has built in the complexity of needing special ballnuts and holders. So, we are asking that our customers head on over to the shop area and preorder their kits. This commitment keeps you keen and us on track. Think of it like crowdfunding.
Following on the theme of top printers, we are excited to be working with Craftunique from Hungary! EmvioENG is an official UK partner, importing, distributing, selling and servicing the Craftbot range of machine!
The Craftbot printer range has, this year, won 2 awards issued by 3DHubs.com
We met the CraftUnique team at TCT in 2016 and have since started importing the Craftbots to the UK. Of particular interest to us has been the Craftbot 2 and Craftbot XL as they are now fully updated with the latest nice-to-haves anyone would like.
Both machines have a very solid build. Steel chassis, Linear rails on the XL and all metal construction throughout. Oh and whats more, you can also specify the colour of the machine you would like! We have the blue one but the anthracite colours are really good too.
Get in touch if you would like to become a reseller
The fantastic value and quality Craftbot 2 has got a bigger brother!
Delivery 7-10 days
As with its smaller brother the Craftbot XL lives up to its reputation of being the best budget printer. With a large buildsize, Wifi, linear rails and a useful nozzle kit, it is hard to beat.
Still using the quick and powerfull CoreXY kinematics, the CraftboXL has shown that even straight out of the box it can print Big and good!
Here it is featured in 3D printing industry news: https://3dprintingindustry.com/news/craftuniques-craftbot-xl-big-builds-budget-100200/
The Craftbot 2 has won the prestigious award of “Winner of the best budget 3D printer 2016” on the 3D hubs website! This little gem offers most of what you would every need in a printer. Fantastic features are of course the WIFI connectivity and an all steel frame for stability and accuracy. Promising you can get from unpacking to printing your first 3D object even in minutes. Comes in a variety of colours too and a truly unique slicing software package!
We are proud to have this machine on our range!
This is not the Craftbot Plus that is not nearly half as good.
Since early July, we have a had a very successful working relationship with Bondtech, the Swedish company producing Dual Drive extruders. The Bondtech extruders without question have brought a step change in reliability of extrusion. Main characteristic of course is the driving mechanism used: Twin counter rotating hobbed wheels.
You know the counter in the machine tools page. Well it is counting down to the 19th of August 2016, the day we unveil our grandest product to date. the unveiling will be done in the Thornbury model engineering exhibition so why not check us out at stand 134.
About 7kg of filament later and lots delightful prints with the BCN3D Sigma we noticed that ground filament and dust had accumulated on the extruder feeder gear. Perfect opportunity to clean the filament feeder by taking it apart, checking out how it is engineered and learn a bit more about the Sigma!
Here is how we did it step by step.
Step 1. Unscrew the socket cap screw shown below to release the bottom Bowden tube. the printed part holds against a nut which is screwed on the tube. Simple and effective!
Step 2. Unscrew the 2 nuts holding the stepper motor board shield and unplug the stepper motor. Try not to lose the tubular spacers! Take them out and store them safely.
Step 3. Remove the top Bowden tube from the feeder by pushing down on the grey ring and pulling the tube out . Then unscrew the nuts holding the stepper motor bracket on the frame. Remove the feeder from the Sigma.
Step 4. Now start taking the feeder apart. Unscrew the large grub screw and remove the tension adjustment spring. Then unscrew the 3 long hex screws which hold all the parts on the stepper motor.
Step 8. Dissemble the feeder and clean all the parts from filament grindings and dust with a small brush. A toothbrush will also do!
Step 9. Reassembly time! Start by placing the aluminium bracket with the bent part facing towards the cables. Then the plastic spacer and pinch levers as shown below.
Step 10. Insert the tension spring through the hole of the top lever and screw in the large grub screw to compress it. In my experience 1 turn after the top of the screw is flush with the lever surface give a good starting point in terms of spring tension.
Step 11. Take the feeder back to the Sigma and fix the bottom Bowden tube on before mounting on the frame, makes life easier! Then slide the feeder on the studs of the frame and fix it in place with the 2 nuts. Connect the motor back to the driver. IMPORTANT! Don’t forge the spacers!!! 2 on each side of the board.
Step 13. Fix the aluminium stepper driver shield back on and insert the top Bowden tube. Done! grabs beer…
We have been asked on a number of occasions, and seen in a number of forums, the question of “How much tension should I put on my drawbar when I use Emvio (or Tormach) repeatable Z tooling?” This question is a very common for those looking to make a pneumatically actuated drawbar using Belville washers. So what do you need to know about Drawbar Tension?
The only way to be sure that any machine is really well designed is to take to bits and have a look inside it! That’s what we did at Emvio Engineering with our BCN3D Technologies Sigma! Oh why not check it out in our shop too
Under the beautiful bottom cover of the Sigma we found the electronics and were impressed with the cable management and over all neat setting.
Then it was time to pull the Z axis out for a closer look… The 2 vertical rods are held in place with welded studs on the frame which made the task very easy. The print bed support made of bent aluminium is very stiff and those side cuts look awesome. The black heat bed sits on a cork pad and both are suspended by 3 springs in triangular arrangement.
I did wonder what was behind the slick looking print heads. Started by removing any screw stood in my way! The nozzle was out and in less than 10 seconds in under a minute the linear slide was revealed. It runs unworldly smooth with no play at all!
Here is the official maintenance video from BNC3D Techonologies showing how easy it is to remove and replace the hotend
To Be Continued..
in the next episode we will take apart the X, Y motion system and extruders!
It is with great pride that we bring to the UK market the products designed BCN3D Technologies.
BCN3D Technologies started off as a project of Fundació CIM, which has more than 20 years of experience in Rapid Prototyping and knowledge transfer. The results have been impressive and that is why when we first came across the company, we were keen to collaborate with them
We will be keeping stock of as many of their products as our limited storage space allows but will be giving priority to the Sigma. As you may have seen in our earlier post, we were giddy with anticipation when the Sigma was released. In no time you will be able to browse our shop for all four of BCN3D printers:
The BCN3D Sigma – The flag ship model that received the best quality award on 3Dhubs page for April
The BCN3D Lux – A SLA machine working with photoreactive resin allowing for fantastically fine layers and printing speed
The BCN3D Plus – A Prusa clone kit aimed at those wanting to build their own printers
The BCN3DR – Another kit but this time for a Delta printer
The BCN3D Ignis – a premium 100W CO2 laser cutter with honeycomb bed and a 900×650 working area
Most of us that tinker with 3D printing have wondered how to reduce the groan and squeal of the stepper motors driving us nuts. Especially when long prints are involved!
For a while now we have been using and selling our own vibration dampers that place a rubber buffer between the stepper and the printers frame. The rubber is thin and stiff enough to maintain accuracy of the stepper motor while reducing the vibrations being transmitted to the body of the printer.