Hi Vily - So 1000N/33um is 30N/um. So if your model is correct look at what bits are deflecting the most. Then address those. Try to bump up the static stiffness. Seems your z axis is the softest...
Type: Posts; User: peteeng
Hi Vily - So 1000N/33um is 30N/um. So if your model is correct look at what bits are deflecting the most. Then address those. Try to bump up the static stiffness. Seems your z axis is the softest...
Hi Vily - Unfortunately, with steel things get heavy. So you are either limited to weight that you can handle or you need to achieve a certain stiffness. See how you go with the FE and stiffness....
Hi Vily - That small free corner will vibrate so cap it. OK FE is a big subject. I apply 1000N at the spindle nose. Use bonded connections everywhere to begin with. Place the gantry at max depth...
Hi Vily - So its 300 high and 200wide? Internal bracing not needed. External bracing has to be on edges not in the middle of a face. It can deflect / vibrate if loaded in the middle of a face. The...
Hi Vily - The HAAS GR-712 gantry machine with X=2.1m and Y=3.6m (similiar to yours) weighs 10 tonne for a reason.
GR-712 | 40-Taper Mill | Large-Platform CNC Routers |Vertical Mills – Haas CNC...
Hi Vily - so on the point of rigidity add an extra section to the back of the gantry. Most of your loads will be in the XY plane so this needs to be stiff. It takes up no extra space in the envelope...
Hi Vily - up to you. Since its a paper exercise at the moment develop both ideas until you are clear for the direction. Mixing servos and steppers is OK. A 5mm pitch screw only needs...
I would say 750W is overkill with the big gearbox on it for Y's Yes you can attach the servo direct to the X ballscrew same as the stepper Oh use a coupling :) Once you figure your needed feeds and...
Hi Vily - The gantry+Z axis is on rails so your only moving the inertia and the friction. Since the friction coeff of the rails is very low say 0.004 you only need 0.004x400=1.6kgf to move it slowly....
Hi Vily - No the holding torque for the motor stays the same so at zero speed you have the full 12Nm. So double the forces just calculated. So at 12Nm (stall or very slow) and 10mm pitch you have...
Hi Viny - What is the weight of your gantry? I see 400kg The Co for a 35mm car is around 70kN ie 7000kg so 3 cars can support 21 tonne? They must use 4 for some other reason... They may use 4 for...
Hi Vily - No need to fill with sand. Ballscrew for X at 5mm pitch is too small. Using stepper say 800rpm max gives you 4m/min rapid. Not fast enough, use 10mm or more. 3 cars on column not needed....
Hi all - Looking at my rotary say D400mm then the planetary at 15arcmin (0.25deg) gives 0.87mm backlash and the harmonic at 30arcsec (0.0083deg) gives 0.028mm backlash so sorting the harmonic for...
Hi all - I have been looking at these harmonics. But I'm unsure which is the output holes or surfaces. I have sent a note to the supplier to explain. Currently my guess is that the D14 is the input...
Hi Craig your machine is a mill and requires higher tolerances then this machine. Mine is a Maker level router for wood and plastics, and being #1 its at preproduction level. I'm sure the tolerance...
Hi Craig - My search for small harmonic drives continues. The planatary I'm looking at has 30arc min backlash (from stepperonline, a couple of years ago they used to be 10 arc min). I'm going to use...
Hi All - The board is now finished and tested. Straight cuts - all good! Peter
Evening all - a small video on my B axis design - Peter
https://www.facebook.com/ScootCNC/videos/973453794343621
Hi Lozz - Can be all of what you mention. Since the machine cuts well slow lets assume we can speed it up. Looking at the cutting data firstly with such a small bit I'd be running it flat out maybe....
Hi Spot - I have several slabs around my house for garages and sheds etc they are 200mm thick and have cracked since laid say 2 years old & I thought the contractor used a lot of reo in them. Here's...
Hi Spot - You maybe doing some stuff right and that will come out when you have a machine running. I only point out stuff that is clearly incorrect in your language, understanding and explanations of...
Hi Spot - Again sorry - the fibre composite industry has very specific definitions of weaving, knitting and tape laying,. I have been involved in all of these. The machine in the video is a tape...
Sorry Spot - Weaving, knitting and tape laying are totally different processes. It is NOT a sewing machine and it is not knitting or weaving. You'll get there one day. Plus if you load a structure...
Hi Qing - Connecting motors in a parallel has issues. I presume by your statement that you want to connect two motors from one driver. Since your making a printer use a printer controller board. Much...
Again Spot - What are the $/kg steel and $/kg concrete you used? I don't want to argue with your costs I want to know the cost ratio to check your comparisons. Peter
Hi Spot - aircraft and high performance boats do NOT use woven mat. They use straight fibres at a fibre volume ratio of around 55-60% so they have space around them for the resin. Really modern stuff...
"fibres need to be in contact with other fibres to have tensile strength" absolutely wrong. I have spliced many ropes and that is a totally different game to fibre composites. Aircraft wings and...
Hi Spot - If your doing manual maths then usually we use the resistor sum analogy for calculating the compliance. So use series or parallel resistor theory or network to calculate the compliance. If...
Hi spot a large scale printer - Peter
UMaine’s novel polymer 3D printer surpasses former Guinness World Record | CompositesWorld
Evening all - I have been working on a B axis for Lanky and Epoch. I'm in the design polishing stage at the moment after a week of chasing my tail with lock nuts... But it has come together and now...