BL Touch sensor review
Fed up with the time and hassle it is to level your 3d printer build platform? I know I am.
Yeah I know you’ve got the auto levelling device, does it work in all situations?
I have a semi automatic one on my delta, the one where you put the microswitch down. Around the back, so you forget about it after you have finished levelling. Yeah – how many times have you thought it would be so nice to have a probe which self parks after use. Click one button on the computer and it takes care of itself.
Well you can.
Introducing the (#amazon link) BL Touch sensor from Antclabs.
This auto level probe for your 3d printer may just save you hours of tedious levelling.
Attaching the BL Touch sensor to your print head – be it a cartesian or a delta doesn’t matter, there are mountings available to print.
Controller being a ramps, sanguinololu, smoothieboard – it doesn’t matter the BL Touch will interface with them all.
Simple to install, only two connector to attach. one for servo and one for level sensor.
Easy to program, coding supplied, just copy and paste. Save and use.
This addon will save you time, precious time that can be used for printing.
A visual indicator shows the probe working, in self test mode and when touching the bed. If there is a problem then an alarm signal will show you quickly there is a problem.
With an automatic bed levelling probe you have mechanical moving parts reliant on the operation of a servo, with the BL Touch there is no servo, just a solenoid, hall effect ic and a tiny computer.
Very little to go wrong.
Giving you the peace of mind that this is one thing you will not need to worry about.
Is it accurate – it has a standard deviation of 0.005 better than the micro switch and servo, with a standard deviation of 0.3. Only the optical sensor comes close, but you are limited on what build platform you can use.
With the BL Touch sensor it doesn’t matter what build platform material you use, aluminium, glass, pei sheet, buildtak, wood it doesn’t matter. Due to the fact that the probe actually touches the platform, It will not get confused.
At 10g this probe will not slow down your delta printer by adding a lot of weight to the effector.
See what others think (#amazon link) here– 88% give it 5 stars
watch it in action
Find other users on google plus
Print your BL Touch sensor mount
black widow mount cartesian printer
https://www.thingiverse.com/thing:1761761
https://www.thingiverse.com/make:261389
delta printer mount
https://www.thingiverse.com/thing:1761852
Technical specs
Voltage 5v
Current 15mA
Peak current 300mA
Z probe output voltage 5v/3v3 selectable
Colour transparent white
ROHS compliant yes
Cable length 150mm
Weight 0.35 oz (10g)
Software comaptibility marlin, repetier, smoothieware
So why not invest in a BL Touch sensor to save you the hassle of manually levelling your build platform. Click(#amazon link) here to buy your BL Touch sensor today and tomorrow you will be seeing perfect prints time after time.
Thanks for reading
phil
The problem with the BL Touch and most other sensors is that they have offsets in X, Y and Z. Nozzle contact probes have no significant offsets and can achieve repeatabilities of the same order or better than mechanical switch based methods.
Mike
Mike – thanks for stopping by.
I agree that there will be an offset, but within the config file this is taken into consideration.
The bed leveling is a relative measurement -not an absolute one, it is to see the state of the bed, tilted or level.
Is there any problem with filament covering the nozzle tip with the nozzle probes, are they force sensing resistors or contact probes?
Auto bed leveling will not adjust for the z offset of your nozzle, it just corrects for any calculated tilt of your bed.
Thanks for the info. I have been experimenting with many technologies used for bed leveling but just as much for setting the nozzle height. My personal favorite is using an inexpensive piezo disc (not FSR) as it is cheap, reliable accurate and has no inherent X, Y or Z offset. Your point about the plastic on the nozzle is well taken but I think I can see a way around that using electrical contact to check for nozzle condition.
Mike
It sounds like you are experimenting more than me. I take it the piezo disc is a releative measurement rather than an absolute one as they are temperature and pressure unstable for absolute values.
I have thought of trying the contact measurement, but only got a spare set of feeler gauges a couple of months ago, so will try using a multimeter and check out the resistance. i can see problems with oxidisation already. i may also add a led to show when contact is made. both of these may work, as long as there is no filament sticking out.
thanks for your update Mike
Phil
Hi Phil,
Sorry that it has taken so long to reply. The piezo discs are used just to detect the moment of nozzle contact and even the quite large variations of sensitivity doesn’t stop the repeatability from being in the 10 micron range with contact pressures in the range of a few grams even with Z speeds of 1mm per second – see the first graph here:- https://forums.reprap.org/read.php?1,635075,page=1
Mike
Hi Mike,
That thread is certainly an active one.
I have found that i have some of the piezo speakers lying around in a box.
Would it be better to put onto the print head rather than the build platform?
This way you only need one and it doesn’t affect te build platform in anyway.
I have not looked into the Z height routine but does it go towards the bed at ‘high’ speed then out and back in at ‘low’ speed to get accurate results?
or does it rely upon the z display being almost correct to slow the printhead down before the impact?
Definitely afree with the use of the diodes after the device, used some of these as speakers in my last job and needed to limit the vibration ‘ back voltage’ to prevent blowing the amplifier up.
Hopefully i will get around to trying this soon. and see what the results are like.
Thanks for the link to the post, some of the immediate questions have been answered – noise problems, voltage limiting, number of sensors.
Are you using three of them mounted under the build platform?
Are they mounted with the same way as shown, does it matter if they do not have the same characteristics?
Just taken a look and found
https://www.thingiverse.com/thing:707392
someone has beaten me to the x carriage mounted one.
I take it you are using it heated?
Phil
Hi Phil,
It should be possible to convert piezo speakers to sensors and piezo discs are also used in things like musical birthday cards and are available as electronic components. DjDemonD on the same forum now sells kits using a single piezo and there are many variations – you may find quite a few interesting ones in the 17 pages of the thread. The Thingiverse entry you quoted at the end of your reply is elenhinan who was (as far as I know) the originator of using inexpensive piezo discs for leveling.
Mike
Hi Mike – I have brought myself up to speed with the thread.
Wow 15 months of work, impressive.
Do you think that manufacturers will take on board your designs?
Or will they stick with tried and trusted.
The other thought is that the piezo can become a health monitor, looking for major knocks will allow the user to be forewarned of any mechanical issues.
Thanks for highlighting this very interesting thread, I am going to see if I can replicate some of the results you were getting, and try out the health monitor.
Phil