Full Version: cannot blast thru rapid mask 3000
From: Peter [#1]
15 Aug 2006
To: ALL
G.day guys,
we have just installed the new sand blast system and we have had our first attempts at blasting some items.
We cannot blast thru the rapid mask 3000, no matter what pressure we are using. Currently we have only a 3mm nozzle on the unit.
we are using 150 grit aluminium oxide grit.
the image is exposed onto the 3000 in the letralite unit, its washed out, but is still very difficult to see, then its dried stuck to the glass/ metal, the clear is pulled off....
( we have tried exposing for 10 seconds, 20, 30, 40, 50, nothing seems to change the problem)
and we try and blast..the oxide simply bounces off the mask without breaking thru.
we have tried, 40 psi right thru to 80 psi..same result...nothing.
the unit blasts vinyl masked items beautifully.
The Local supplier tells us that it is because we over expose the film , because our workshop has too much natural sunlight coming in thru all the skylight glass?
Could we have exposed all the film to UV light each time we took it out of its foil protective envelope thereby rendering it useless ?
How much light is too much?
would exposing the image in the letralite, then taking it outside to wash it out overexpose it?
regards
Peter
EDITED: 15 Aug 2006 by PETER
From: Harvey only (HARVEY-ONLY) [#2]
15 Aug 2006
To: Peter [#1] 15 Aug 2006
might be the culprit. Sunlight contains a very large amount of UV. Even through clouds.
My uneducated opinion from using similar products years ago is that everything to be blasted needs to wash out completely, or nearly so. A faint image in a proper washout would indicate some general exposure or far too much exposure when making the mask.
Hopefully someone who knows what they are talking about will also answer.
From: gingem [#3]
15 Aug 2006
To: ALL
Hi Peter
Sounds to me like you are doing one of 2 things wrong,
1- you are exposing the wrong side of the film when developing
2- you are not removing the carrier sheet after applying the mask to the piece.
Everyone talks about extra light bothering film. We use regular fluorescent lights and have windows near where we develop all of the time. We do a lot of blasting and have never seen this to be a problem. I use Photobrasives UltrPro 5mil film all of the time. We used to use Rayzist film but I prefer PB's film.
From: Engravin' Dave (DATAKES) [#4]
15 Aug 2006
To: Peter [#1] 15 Aug 2006
Peter,
I am not familiar with RapidMask 3000. In the US, RapidMask is a non-washout product. Are you using SR3000 Photo-Resist Film from Rayzist?
A normal washout type film would completely wash away without being exposed, so it is the UV exposing that creates the chemical reaction that makes the areas around your image non-penetrable. The fact that you are not able to wash out the image completely tells me that the actual image area is being over-exposed at some point during the process.
What type of printer and paper are you using to create your image? Your printer may not be creating an opaque enough image on your vellum to block the UV light from coming through and hitting the resist.
EDITED: 15 Aug 2006 by DATAKES
From: Peter [#5]
15 Aug 2006
To: Engravin' Dave (DATAKES) [#4] 15 Aug 2006
Hello David,
Sorry its too early am for me
its SR3000, we are currently only trialling the samples that came with the kit.
so the artwork is perfect. we have both vellum and laser clear samples.
as I said we have exposed for 20, 30 , 40, 50 seconds and more ,none of the times make any difference.
Our workshop is very well lit with flouro lights, as well as having large skylights and we have washed the image out, outside.
thats the problem , you reckon?
Is a dark environment important ?
regards
Peter
From: Engravin' Dave (DATAKES) [#6]
15 Aug 2006
To: Peter [#5] 15 Aug 2006
I personally think that is your problem. I have a fixture in my work area that is on a separate switch and has a UV blocking film over the acrylic cover. I have the same thing in my washout area. When it is time to do resist developing, the regular lights go out and the UV resisted lights go on.
Do you have a mop sink in your building? Something that is on the floor like this one.
EDITED: 15 Aug 2006 by DATAKES
From: Harvey only (HARVEY-ONLY) [#7]
15 Aug 2006
To: Peter [#5] 15 Aug 2006
There is one other possibility. Getting things to down under takes a while. If the film was overheated for a while that would also cause it to polymerize.
Try washing out a scrap inside without any exposure. If it does not wash out the film has been compromised in transit.
EDITED: 15 Aug 2006 by HARVEY-ONLY
From: Peter [#8]
15 Aug 2006
To: ALL
all fixed , thanks for all your help !
regards
Peter
:-)
From: UncleSteve [#9]
15 Aug 2006
To: Peter [#8] 15 Aug 2006
All fixed? My cat was "fixed" and we didn't even know it was broken... >.<
From: Ozzy Fox (CLIVEGARAWAY) [#10]
15 Aug 2006
To: ALL
I'd say Bill was right when he said "exposed the wrong side of the film or maybe washed out the wrong side of the film....We've all done that before,
Fess up Pete.............
regards Clive.
From: Peter [#11]
15 Aug 2006
To: Ozzy Fox (CLIVEGARAWAY) [#10] 15 Aug 2006
ok,
I just call the shots...very rarely do I actually push the buttons..
Our production foreman, puts the machines into action....
Today, I went thru the motions of doing what we were meant to do..followed the instructions...no different to our brilliant production foreman..who does all the hard thinking in the workshop...
No different to all the advice and instructions..
the only thing I did different was wash out the image for 2 mins rather than the 30 seconds recommended..
and....guess what...the thing darn well washed out.....!
we only had access to cold water until this afternoon..all the latest images are being washed out in warm water and in fairly rapid time.
te problem was simply...we were washing out according to instruction or even up to 60 secs more....but in cold water..
it simply wasnt happening...
all fixed now !
thanks guys!!
From: Ozzy Fox (CLIVEGARAWAY) [#12]
15 Aug 2006
To: Peter [#11] 16 Aug 2006
Peter,
Get the guys to use a white backing plate to wash out on, then you can see thru the film exactly what is washed out, it should be easily visible., yes cold water is a problem, be careful not to overwash with warm or even too hot water though as it can ruin it just as easily. with hot water the edges blur and the resist goes "gooey".
cheers Clive.
From: Engravin' Dave (DATAKES) [#13]
15 Aug 2006
To: Ozzy Fox (CLIVEGARAWAY) [#12] 16 Aug 2006
Peter,
I will second what Clive said. Use a white clipboard and warm water, not hot. There is an acquired skill in timing the washout process. There is a fine line between too washed out and not washed out enough. I'm glad your making progress. Your customers will be thrilled.
I'm still curious if you have decided what you are going to use for printing your images. We could share some guidance in this area as well.
I personally have had years of success using a laser printer and vellum. This is a much cheaper process than inkjet and the more expensive, specialized paper you have to use to get an opaque image.
EDITED: 15 Aug 2006 by DATAKES
From: Ozzy Fox (CLIVEGARAWAY) [#14]
16 Aug 2006
To: ALL
Like Dave I also use a basic laser printer and vellum, if the image is not dark enough or you have very fine lines then I use a spray can of Krystal cote which darkens the image and helps the process. I also found not to trust the letralite timer I use a second hand on a watch and for between 19-21 seconds,and I mean BETWEEN 19&21,
(maybe 2 seconds more on 5 mm resist.).
I have not found the fluro tubes or UV to cause me any major issues, I cutoff what I need and put it away, expose the job, washout, let dry, stick on and blast, usually 15-30 mins depending on drying time.
regards Clive.
From: RALLYGUY (RALLYGUY1) [#15]
21 Aug 2006
To: Peter [#5] Unread
A UV safe environment doesnt have to be dark. They sell yellow light covers that block uv from fluorescent lights. We use these in our screen exposure room (similar process and chemistry as resist materials).
This may be the ticket, if you're having over exposure issues.
One way to test is to take a coin and a fresh unexposed section of material. Immidiately place the coin on the sheet and leave out for an estimated amount of time that you would be working with the materials. Apply to product and try to blast the material. If you are able to blast the coin shape properly, it is likely that you are exposing the material too much while processing, and need either shorter processing times or better UV control.
If it acts the same, you are having other issues...one of which could be bad material, or as someone else mentioned, you may not be removing the liner properly. This liner if left intact would protect the resist from blasting, and could theoreticaly act the same.
Hope this helps......
From: RALLYGUY (RALLYGUY1) [#16]
21 Aug 2006
To: RALLYGUY (RALLYGUY1) [#15] 21 Aug 2006
From: UCONN Dave & Lynn too (DANDL48) [#17]
22 Aug 2006
To: RALLYGUY (RALLYGUY1) [#15] 22 Aug 2006
Where do you get the UV covers?
Thanks,
Dave
From: RALLYGUY (RALLYGUY1) [#18]
22 Aug 2006
To: UCONN Dave & Lynn too (DANDL48) [#17] 22 Aug 2006
I believe Midwest Sign and Screen has them....Any Screen printing supply company should have something like this.
http://www.midwestsignandscreen.com/index.html
Looks like they have a location in your region...... :)
EDITED: 22 Aug 2006 by RALLYGUY1
From: Engravin' Dave (DATAKES) [#19]
22 Aug 2006
To: UCONN Dave & Lynn too (DANDL48) [#17] 22 Aug 2006
Dave,
If you light fixtures with lenses you can get UV blocking film at any hardware store and cut it to cover the lens. It is usually with the other tinting films.
After cutting to size, just open the light fixture set the film in place, then close the fixture. You are good to go.
From: RALLYGUY (RALLYGUY1) [#20]
22 Aug 2006
To: Engravin' Dave (DATAKES) [#19] 22 Aug 2006
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