Anyway I started by looking for a 600x900x100mm+ desktop router for hardwood and came upon the JBEC model on ebay. Following further research it's evident the 5 to 10k market is a minefield with machines ranging from crap to good (for the money). I was looking around the forum for 'best buys', without much luck, when the EXEL link appeared so I'm thinking this brand must rate as quite good. It's funny the JBEC machine chooses to use the rails it does because it seems easier and better to use off the shelf linear bearings for the job in the knowledge they are tried, tested and reliable. Maxicam machines look quite good, also BZT, Heiz plus a load of others and after reading some of the posts I think I'm aware of which ones to avoid. I would need a decent spindle with an ER20 chuck and that was what lead me to the JBEC machine as some of the others were offering just 1/4", 8mm max. I will be contacting EXEL tomorrow hopefully to get prices etc. One thing I've noticed is that manufacturers quote the Z axis travel but don't give any details of height under the gantry, it would be ideal if they gave the bed to collet height at one extreme of the Z travel.
The Following User Says Thank You to Gytis For This Useful Post:
Apologies for absence in this thread guys. Have been very busy. Great to see a pointed discussion going on about the 5-10k price bracket for a CNC router. EddyCurrent - fair play - your questions are what every prospective CNC router customer should be asking.
Keeping on the slightly diverted (but welcomed) thread content, we would also be very interested to hear the prices, availability, leadtime, control packages, software and support offering from EXEL and the all important
In relation to the slides and bed stiffness I'm working on it. I hope to have more information as soon as I can get it together coherently.
In the meantime keep the debate going.
Anyway I have not commited to buying any machine yet so it's still wide open.
There is a video of me perched on the machined bed. And subsequently on the Gantry. I''m tipping the scales at over 90kg... 90kG is about 880N. no rude comments please... ... So that is 90kg going through the surface area of my scruffy shoes in the middle of the machine - and then around the machine a bit. I then stood on the gantry in the middle - somewhat precariously.
whats the going weight of a 8 foot by 4 foot sheet of 3/4 ply? over 30kg.. ish?
I also have this vide below if it is of any value here. The UC100 that we offer from CNCdrive motion controls is a nifty little gizmo. I'm sure most of you are aware of / have seen some issues with Mach3 running on windows. Windows put up the road block to the likes of Artsoft that is, they don't let you have control over what the processor does and the PC hardware has to generate the control logic for the drives... The result is potentially poor performance that is nothing to do with the machine but to do with the pulse streams to the machine. Now in fairness to Artsoft, to produce a software package able to be as cross platform compatible as well as they have done is , in my opinion, very very impressive. Mach 3 also is also invaluable in its ability to customize, tinker and add I/O etc. Something the bigger manufacturers just don't do.
The new generation of motion controllers like the UC100 as well as the Smooth stepper, PlanetCNC USB etc etc are allowing industrial CNC control to happen on a desktop PC. The DSP in the controllers generates the pulses to the steppers independent of windows. The communication between the PC and the controller DSP occurs via a USB with the UC100 as examples. In these examples, processor intensive tasks on the control PC can be carried out without compromising the quality of motion of the machine.
The max rapid feed you can get on Mach3 running with a Kernel Speed of 25kHz is a tad over 9,000mm/min? Please correct me? Granted you can increase the kernel speed to increase the feed but you put pressure on the PC hardware. The 15mm/min feed rate shown in the video is there not to demonstrate the the machine can whizzz quickly - its meant to convey the importance of clean pulse streams for reliable machine operation. It is equally necessary for slow movements and for 3D machining where 3,4 and 5 simultaneous pulse streams may be required.
It is also worth noting that you can spec a top of the range W7 64 bit PC packed to the gills with ommph and you'll possibly get better performance out of an old Pentium machine.
if its felt that this is not valuable to the current thread context let me know and I'll move it elsewhere - I did a quick search - if there is a thread where this content would be more suited - let me know.
more details to follow on other machine aspects.
Last edited by StoneyCNC; 25-08-2013 at 02:42 AM.
If your going to bother with this stuff then Better IMO to apply some lateral tests simulating real world cutting forces. . . . . Push & pull on the bugger in all directions and lets see how it jiggles.!!
Regards the Motion control card then I'm a big fan of them and thou I haven't tried the one your using I have most others and they can make a huge difference to speed performance (which doesn't mean much to me.!) but more importantly how smooth the motors accelerate and perform.
That said I much prefer Ethernet over USB has it's much more reliable, USB can be touchy and shouldn't be relied upon for providing power has it's very flaky.
Edit 2: Not all motion control cards are equal thou so anyone seeing this and thinking to buy then please checkout before doing so has while they all tend to offer smoother pulse train etc they can lack or be flaky on over features they have to take over from PP, like spindle control, Homing/limits functions, Backlash comp etc.
EDIT: Ok years of tuning race engines has taught me that the ear is a highly tuned indicator showing when things are running nice and smooth.!! . . . When I ear growling noise's I get concerned to why.? (growling = vibration)
The growling I'm hearing I believe to be those linear rail bearing blocks on the Rails.?
So with that I'd request a Video of all Axis disconnected from the ball screws being manually worked both fast and slow.!!
Last edited by JAZZCNC; 25-08-2013 at 12:05 PM.
It demonstrates the tower stiffness and that there is no slop/deflection when my 90kg..slim fame puts pressure on the gantry and the slides. It also shows that when you move the load point around the bed does not twist up and deflect. Will look to get other data too.
to keep the threads cleaner and on topic I've put this here http://www.mycncuk.com/forums/manufa...n-control.html
Last edited by StoneyCNC; 26-08-2013 at 01:42 AM.
In relation to the comments and opinions that have been put up on this thread we have had a meeting with JBEC and the German machine builder and had a discussion. Firstly we would like to be clear on a few key points in this response so that the message is not taken out of context. We would also like to advise the general audience of this forum to be mindful of relativity and comments and opinions that can be taken out of context.
- Profiled rails (THK and HIWIN for example) are the best linear translation system for a CNC application.
- There is a mine of exceptional information on this forum and the active members go to significant effort to help others and in our opinion are enhancing the CNC community in the UK no end – we commend this – it’s a fantastic resource.
- We are of the opinion that there is a disconnect on the forum between a commercial CNC system and a full on informed home build. The two approaches in terms of the manufacturer and the end user fall into very different categories. The general jist of what we have read on our, and indeed other posts, is that “nothing is ever perfect”. We would ask the general audience to consider the difference between a home build DIY CNC machine vs a machine that is produced in volume, commissioned with training and supported actively by the supplier. The two scenarios are very different and the perceived “value” needs to be put in context.
- We approached this forum with the aim to help the CNC community be more productive and to offer our share of experience to those interested or looking for help – as well as to inform of the products we offer. We felt our experience and ability to supply CNC equipment and control products could benefit the community.
- We are not here to make a quick buck, we believe in our system and our reputation in IRL. We would not be offering and supporting the system in the UK if we did not stand by it.
- Anyone who feels they have the ability to do a DIY CNC home build should do so and spend the money and get the extra functionality. This extra performance comes at the expense of your own time to make it happen and the inevitable head scratching. If you ever give yourself the opportunity – do it! You’ll not regret it.
- Those who opt for an off the shelf solution should be given access to a fair and honest information source about the relative performance aspects the CNC systems on offer.
There is no question that the linear profiled rail and carriage system is the highest performing linear mechanism there is for CNC applications – hands down. Linear rails are the only system that can provide load ratings for even the most-high spec CNC applications only allowing motion STICTLY in their desired direction of movement. However, the tolerance levels demanded of a CNC system using profiled rails is in the order of microns in bed tram and global machine alignment. This is why when you look under the bonnet of any big commercial machine they will be there.
Typically therefore, linear rails suit machine builds where solid steel or equivalent machine beds are machined with precision to take such a rail system and to realise the accuracy they can provide. Either that or great lengths and effort have to be gone through to make them work on other frame designs. Applying a linear rail does not add the performance of the rail system if it is not backed up by the bed design, precision and stability. Only then can twist and tram be true and give the level of performance that the rails can realise. In order that the performance of such profiled rails can be fully realised depends on the bed design.
Hats off to Jonathan’s latest build http://www.mycncuk.com/forums/router...g-machine.html. What a great insight into CNC machine building - the level of detail and open source nature of the build is fantastic and there is no questioning the level of work that has gone in and the result is a good machine – the video speaks for itself. For someone looking to build a machine this and other such posts on this forum are an exceptional source of information – far above and beyond any consultancy invoice. Hard detail is given at every step - invaluable.
Contextually the build has highlighted the importance of the bed alignment in a CNC system. The welded frame predictably has twisted and bent from the thermal loading generated by the welded frame and this design decision has challenged the use of a profiled rail from the outset. This has been clearly illustrated by the work required to align the rails on the machine and to align the machine for accuracy – tram and twist etc. It may well have been the most cost effective frame build in a DIY context but it is not sustainable commercially. Also the estimated price tag of 4-5k not including the time and extensive know how gives the general audience a feel for the cost and effort that goes into a “sufficiently stiff” CNC router. There is also the question of relieving the stresses in the welds and the long term stability of the bed.
There is also the question of Mach3 lost position? Possibly due to missed steps perhaps due to some slight lock up – eliminated by the cleaner pulse trains from Linux giving more motor performance perhaps? Unless there is a software issue with Mach (not passing the driver test – or other quirk) then the software fix (move to linux) has potentially overcome what is actually a hardware issue? Perhaps there was a motion controller used with Mach3 and not a LPT - in which case the previously stated possible issues are invalid. These and other comments are based on images and description and are therefore limited in the amount of information available and cannot be taken as conclusive, but purely observational.
In the words of JAZZ “First let me say not going to pull it apart or condemn because the machine is very well thought out and professionally put together” The comments and message in the previous two paragraphs are aimed at putting some context behind what we feel have been very strong statements towards our design on the basis of a “digital viewing” – handed over in detail and in a timely fashion not attempting to “hide” anything – but in essence are only observational context.
If every second machine didn’t work with Mach we couldn’t offer it. It has to work every time, every machine. The machine has to be stable long term. The bed is put together with refined assembly processes in Germany. The system is very portable and retains its performance in transit and does not require any tuning on arrival. It arrives and it works. Here are a few videos of the machine being put through its paces. (no backlash/geometric compensation was used in any video posted to date)
The JBEC CNC router series linear slide system went through a full digital mock up (DMU) and was also been mechanically tested and refined in a physical kinematic system analysis. For intellectual property reasons further details will not be disclosed. On the bigger machines with a different application space profile rails are used. We are working on a bigger machine currently that will indeed adopt profiled rail due to its size and performance parameters and consequently will have a bigger price tag.
We feel that such severe comments should not be made on the basis of a digital viewing without access to materials, BOM with fits and tolerances. We, JBEC and our German colleagues welcome criticism based on the machine in action and subjected to tests.
In light of the above post content JBEC wished to explicitly convey the following message.
- JBEC has opted not to use welded frames in CNC builds as it is too difficult to machine/prepare the frame surfaces for profiled rails. It is viewed as not a viable option to mount a profiled rail on such a system commercially.
- JBEC has concerns over the use of welded frames long term, as table stability will be a major concern. Any stress relief or shift in the frame alignment will cause the rails to misalign and the machine will lock up/ torque out.
- JBEC strives to match the components to suit the design/market sector and end user and to provide an economical and fair cost basis.
- JBEC recommends the use of only HIWIN or THK Rails on the larger Bed type machines which will be made from machined steel to maximise the accuracy and precision
- The JBEC series machine is tried and tested, has long term stability and hits heavy in the functionality and performance on offer in the target market and is more than fit for purpose.
Our German machine builder is of the opinion
that a commended and tested design should not be likened to a skateboard for the reasons stated heretofore.
Our philosophy is that CNC technology empowers people, business and education, and that the product, correctly placed and supported with appropriate training, can help to provide new employment. The JBEC system and CNC support is helping to grow small and developing SME’s in Ireland and JBEC has seen a rise in the level of production here as a result of the machines sold into the Irish market to date.. Indigenous business growth is an important economic pillar in the fight against mass production from abroad. We don’t manufacture indigenously enough here...... This needs to change. It is for these reasons and due the demand for a professional CNC router platform within this price bracket that we have taken on supporting the machine both here in Ireland and in the UK.
We were curious as to why some of the competition was not present here and we now have a feel for possibly why.
It is important to recognise that there is a goldmine of detailed information on this forum and the active members do a great deal for members and go to significant effort to help out members and in our opinion are enhancing the CNC community in the UK no end – we commend this – it’s a fantastic resource. It is also VITAL for safety aspects of CNC when people try to build machines.
However we are considering whether or not to continue with a presence in this forum. We set out to provide and support a professional CNC router with the best available components and within a modest budget. We are confident that this has been achieved with the JBEC Professional Series, that the machines themselves will “do the talking”, and that we welcome any further enquiries at email@example.com
We are now an official supplier of Mach3, CNC Drive motion control electronics and of the Fogbuster coolant delivery system.
For what its worth here are a few examples of work done in house just to show that we are not just a CNC supermarket.
Aluminium bike parts
In house machining
In house machining
Built enclosure for small machine
By martin54 in forum Milling Machines, Builds & ConversionsReplies: 67Last Post: 13-09-2013, 11:35 AM
By StoneyCNC in forum Manufacturer NewsReplies: 29Last Post: 15-08-2013, 05:59 PM
By poppa jock in forum Machine DiscussionReplies: 0Last Post: 29-07-2013, 04:43 PM
By Tenson in forum Swarf & Chip ManagementReplies: 6Last Post: 08-04-2013, 12:59 PM
By Ricardoco in forum Gantry/Router Machines & BuildingReplies: 19Last Post: 17-07-2012, 10:12 PM