4' x 4' x 8" Router Build

[Kitwn]

I haven’t looked at the data sheet for the sensor but. I’d assumed that it would be triggered 2 or 3mm before contact and I could then have the hard stop almost flush with the sensor z. How much overrun should I allow for? I guess when it’s travelling at speed something like 5-10mm would be better?


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You need about the same length as a piece of string! All depends on the weight of the gantry, your approach speed for homing (crashes at rapid speed will hopefully be avoided by soft limits once the machine is homed which is the first thing you will do after switching it on) and some stuff to do with drivers that other regulars will understand better than me.

Your Z and other axis (it's Y on my machine but X on many) sensors are right. In practice the overlap of the sensor and your target will not be very much when it triggers. I put slots in the mountings of my targets to make things adjustable but this does increase the risk of something moving and messing up the repeatability of homing.

Kit

[JAZZCNC]

I haven’t looked at the data sheet for the sensor but. I’d assumed that it would be triggered 2 or 3mm before contact and I could then have the hard stop almost flush with the sensor z. How much overrun should I allow for? I guess when it’s travelling at speed something like 5-10mm would be better?


Sent from my iPhone using Tapatalk

The distance is determined by the sensor spec, if using just for homes then 2-3mm won't be a problem but if using for limits then usually you will be traveling at fairly high velocity when tripped so the inertia will easily travel 1-2mm if at high feeds.
Also, the accuracy and sensitivity are affected by distance, so it's best to keep the distance on the smaller side of the sensor spec. This way it will react faster but obviously if end on you have less room to stop. 90deg is a much safer setup.

[JonnyFive]

Finally got around to sorting the proximity sensor bracket:



I think I'm finally there with the design, still need to finalise the motor choice and sort out some sort of levelling feet - can't decide whether to add levelling casters, they're pretty expensive but probably worth the money if I ever need to move the machine. At the minute I've just got M12 nuts welded on to the base of each leg - they look a little small to me but it seems M12 feet are good for 1000kg each - should be enough!

[routercnc]

I made some steel discs as targets for mine as the sensor will be more sensitive than on aluminium, but both will work.

[JonnyFive]

Just been pricing up the steel to make my frame, the price has gone through the roof!! Almost double what it was when I last looked!! Ouch!

[JAZZCNC]

Just been pricing up the steel to make my frame, the price has gone through the roof!! Almost double what it was when I last looked!! Ouch!

Tell me about it, and it doesn't just stop at the steel, aluminium has also gone crazy. The price of steel is also driving up the price of motors, ball screws and anything else made with steel. Then on top of this shipping costs have gone crazy.

[JonnyFive]

That’s all I needed to hear, how am I going to explain it to my missus?!?

[Clive S]

That’s all I needed to hear, how am I going to explain it to my missus?!?

Do you need to tell her

[reefy86]

I am in the same boat as you. 2018 was the last time I was on here and almost was ready to start it after 2 years of learning and designing from some really top guys on here. It was so easy to source materials and mild steel box sections was cheap as hell but now as you say they have doubled in price and I can't even find any suppliers for ball screws and the ones I have for linear rails they only stock a few. Not even looked at the electronics side yet. Dont know if I should just save money and wait to see if things go down and new suppliers start selling or keep searching and hoping for the best.

[JonnyFive]

Tell me about it, and it doesn't just stop at the steel, aluminium has also gone crazy. The price of steel is also driving up the price of motors, ball screws and anything else made with steel. Then on top of this shipping costs have gone crazy.

Jazz - do you have a feel for how much things have increased overall? Has everything doubled? Just trying to estimate how much extra I need to find.