Envision 375 X Axis calibration

[Alex P]

Hi,
Sorry that this is my first major request here, I have an Envision 375 and the cuts seem to be off by roughly 0.5mm on the X travel (Vinyl in/out) . Basically if I try to cut a circle or square these are smaller by 0.5mm in this direction compared to Y Axis which is near as dam bang on to what is on the screen in Composer 5.0
Is there a calibration that can be performed on this Envision by the user without getting an engineer involved?
All belt and pulleys are all okay along with the bearings, cutting strip is new.
I'm not refering to the calibration on print/cut registration by the way - this is just cutting vinyl only.
Thanks in advance,
Alex.

 

[Joe House]

Alex, first make sure that there is no adhesive buildup on the sprockets. That can lift the holes up higher on the teeth and allow some slop in the x direction. Also, I always try this test with genuine Gerber vinyl. They put a patent on the hole punch configuration and some manufacturers got around that by using an alternative punch pattern that can also cause slippage in the x direction.

 

[Alex P]

Hi Joe,
Many thanks for your reply, All the spockets are clean and free from residue, All the gears are fine along with all bearings as these have all been checked. Whether I use genuine or other sprocketed vinyl it doesn't change the end result. There is no play or slippage anywhere in the X/Y movement. Basically cutting squares results in a shortage of up to 0.5mm on the X direction. Cutting circles are the same - however these also have a slight flat top and bottom like the a poor quality circle cut if that makes sense? Roughly any diameter and any speed results in the same issue. Cutting the same file on my GSX Plus is perfect so it's not the file design. There's nothing mechanical in the machine that I can see which could be causing the issue and was wondering if there was a service manual available to download or purchase so further investigation could be done.
Thanks in advance.
Alex.

 

[Alex P]

Well this Envision 375 has got me stumpped, I found a damaged Y axis ribbon cable thinking this might solve the cutting and plotting issues but after repair the problem is still exists. There is no play/ backlash in any gears in both X/Y motors/ gears but I'm still getting poor plots with the test wheel and poor cuts using the XO8 test. I'm pretty sure now the machine is mechanically sound as everything has been checked/ tightened. I've ran both friction tests but it seems they just go on for ever and never finish? Am I missing something with these tests and what they do?
I've attached a photo of the plot test run at 10" sec speed and 0 corners for the pen. It clearly shows the flat part at the bottom of the wheel and lines that do not match back to the centre.

 

[FunkotronXL]

Your wheel image is interesting. How old is your blade holder (the bearings can wear out)? What angle blade are you using (OEM or aftermarket)? What brand and variety of vinyl are you using (cast, calendared, mil, age of stock)?

 

[Alex P]

This plot wheel test is using the pen at zero offset, The X08 cut test is done at .020" (.500mm) offset using Edward Mathias smart knifes. These are brand new so I know it's not blade bearings in these as I've two of these and they both have been tried. The Plot Wheel test just uses a pen and similar inconsistencies are replicated. I've used different sprocket vinyl but still the problem exists across whatever vinyl is use. I have a trusty GSXPlus that i use as the main plotter and this has no issues at all, Print and cut registration is bang on and cut sizes are replicated from software to output on the vinyl to 0.1mm (.004")
Other than one of the motors going bad I really don't know where else to look, The machine is stripped as much as I dare without undoing any mechanical encoder setup as I'm without the service manual (if such a manual exists I would be most greatful for a copy)

 

[Alex P]

One additional note - I've compared and measured the sprocket pins on my GSXPlus and FX printer and they all measure on both of these around 3.90mm to 3.95mm dia at the base, however on the problematic envision nearly all my pins (both sides) measure around 3.15mm to 3.30mm dia at the bases and also are all worn in odd ways? Maybe the vinyl is actually moving around the smaller pins and causing my cut and plot issues. Next question - can these pair of sprocket wheels be purchased separately? If the price is extortionate I'm thinking of getting small over caps made to the original size and glue them on the existing worn pins just to see if this is the actual cause of my issues with this plotter?

 

[FunkotronXL]

One additional note - I've compared and measured the sprocket pins on my GSXPlus and FX printer and they all measure on both of these around 3.90mm to 3.95mm dia at the base, however on the problematic envision nearly all my pins (both sides) measure around 3.15mm to 3.30mm dia at the bases and also are all worn in odd ways? Maybe the vinyl is actually moving around the smaller pins and causing my cut and plot issues. Next question - can these pair of sprocket wheels be purchased separately? If the price is extortionate I'm thinking of getting small over caps made to the original size and glue them on the existing worn pins just to see if this is the actual cause of my issues with this plotter?

Image you supplied for the X08 test is good to see. How thick is that vinyl?

Is the envision very old? Owned one for over a decade with thousands of yards of media run through it; never had to replace the sprocket wheels due to wear. Replacing the wheels is not easy, field tech install or service overhaul. A service overhaul usually throws the kitchen sink at it and replaces a handful of different parts. Cheaper to just swap everything than to sleuth it.

If it is hardware based it'll likely be that tiny board underneath the carriage assembly.

My experience from long term usage of both the GSX and Env375 is to not expect extreme accuracy from the Env375. Circles = GSX, everything else = Env375. Unless you're working with extremely tight bezels or inlays, a plot accuracy of 0.1mm is generally acceptable under most circumstances.

Don't trust anything past 0.01" due to math conversions from software. Usually thousandths of an inch (0.00X") round to the nearest hundredth (X.001-X.004" = X.00" and X.005-X.009" = X.01")

The sales people say the Env375 cuts circles. It cuts egg shapes (not ovals, ovals are uniform and consistent).

 

[Alex P]

The machine date from labels inside the machine indicates 1999. The vinyl is 65mic hexis suptac but I use a host of others. Looking more at the pins and comparing them to my other machines - they really are badly worn, seem like little teeth rather than pins and well undersize compared to the other FX and GSX I have. I'm quite capable mechanically to replace these sprocket wheels but not able to reset anything encoder wise on the X axis sprocket wheel if it requires it especially without the service manual. Looks like more fault finding and testing is required.
I'm shocked to hear that cutting circles isn't good or expected on the Envision, how can you be expected to pay £6999 plus tax UK for a machine that is so poor. My old GSK cuts slow but perfectly. Cheap Chinese plotters also cut perfect.
The circles cut on the Envision are indeed skewed.... Not round and not eclipse but just skewed?

 

[FunkotronXL]

It is perspective based. The envision makes good circles on thinner materials, unless you are a perfectionist. Increase the thickness and they get gradually worse. The largest advantage between the two is of course the Env375 is way faster. They may have improved the Env375 marginally since 1999, you're plotter is considered an adult in the US based on age.

Take a clear material with a clear liner and flood them with different transparent colors over a short plot file with multiple circles and oval sizes mixed in. Run the same plot file on both the Envision and the GSX and check for color shift on the edges of the shapes after weeding the excess.

Have you checked if the sizing issue scales or is it a static reduction of 0.5mm?

 

[Alex P]

The same file print and cut on the FX and GSX as an unform shift by 0.1mm to 0.2mm (.004" to .008") but I put this down to non genuine foils and also bombsite alignment. The cut shapes are no where near as accurate using the Envision at the moment. My main focus is now the pins as now I've compared against my other machines the Envision sprocket pins look so bad. Pic 1 is Envision, Pic 2 is GSX and Pic 3 is the FX. I'm guessing the previous owners must have used a wire brush to clean off the glue around the pins - struggle to see how the condition of these pins is so poor.

 

[FunkotronXL]

The same file print and cut on the FX and GSX as an unform shift by 0.1mm to 0.2mm (.004" to .008") but I put this down to non genuine foils and also bombsite alignment. The cut shapes are no where near as accurate using the Envision at the moment. My main focus is now the pins as now I've compared against my other machines the Envision sprocket pins look so bad. Pic 1 is Envision, Pic 2 is GSX and Pic 3 is the FX. I'm guessing the previous owners must have used a wire brush to clean off the glue around the pins - struggle to see how the condition of these pins is so poor.

I would say you've found your issue. Never seen sprocket wheels that bad. Good luck sourcing the parts!

 

[Alex P]

Well I finally managed to purchase and receive the replacement sprockets for the Envision.

Fitting wasn't too bad but just requires a methodical approach when taking this machine apart to the level it needs so the main shaft can be removed. Gave it a good clean whilst in there with new end bearings and cap heads where necessary. Also had to set both sprockets so they were in alignment with each other but there's a square (diamond shape) cut out on each end I guess for this and I just had some square stock the right size so I could align and clamp each sprocket along the main shaft .

Ran a quick test plot and also a X08 cut test after rebuilding it to a stage it could run and preliminary results are a massive improvement on what I had with the worn sprocket pins, I would hazard a guess this is as good as it's going to be with the new sprockets.

But so far so good and hopefully this was the issue all along with the vinyl moving on the pins during travel. I still can't believe how bad the pins were as past owners of this machine must have use wire brushes to clean the glue off. The parts were expensive but didn't have much choice other than fix it with new sprockets of have a expensive door stop.

 

[Jburns]

WOW! those pins are really worn!! those pictures show a stark contrast.
I think you are right - previous owner used a wire brush - maybe a grinding wheel!

 

[Joe House]

Nice Job!