PDA

View Full Version : Mold polishing method/tools



Wiseco
07-13-2006, 11:27 AM
Hi,

Just to start a debate on this :

How do you polish your molds to get a mirror finish?

Do you made it by hand?
Do you use a tool like a luster from NSK?

At our shop, we made it by hand with sanding paper from 320 grit to 2000 grit and to finish with a polishing paste called Polisol. We are thinking to buy a luster but don't know if it can do the job. This is why I'm here asking this. I would like to have some advice on what not to do with some material. I've ever heard that a paste with ammoniac is to be avoid in aluminium.

Also, I'm searching a place where I can have information on finish. I know they are grade like A-1, A-2, A-3 finish, but never see a chart that explain each finish with picture.

It would be great if we could make this thread THE PLACE to get information or links on this.

Thanx!

Edit: I've post this thread here as the polishing is a big part of making a mold.

Tebis
08-26-2006, 01:39 AM
Depends on the finish you get from the machining,sometimes I start with 180-220 and go all the way up to 1500grit.I use both paper and stone.Then I'll use different grades of diamond compound.

9lrac9
08-26-2006, 03:09 AM
It's simple stuff... You can spend 4 to six hours prepping the mold after machining with wax, 120 grit wheels, and a die grinder. Then hand finish with sand paper and kerosene, draw polish from the bottom, deepest part of the mold to the parting line, not top to bottom, side to side. The more care on the sanding with the paper and the kerosene the finer the polish job will be, as the more scratches you get out the better you job will turn out. PS I used to polish blow molds for water and soda bottles, which the molds have a mirror finish. and dairy bottles made of Beu, ie Copper berilyium.


9lrac9
PS you can buy all you need at a good industrial hardware store. Polish...

Tebis
08-26-2006, 10:19 AM
when I use 400+ paper and certain stones, I dip them in EDM oil and polish away.But be very gentle when you polish,do not put to much pressure or else you'll creating more scratches.

Wiseco
08-28-2006, 09:50 AM
So as I understand, most of the polishing is still done by hand.

Does anyone use a Luster like this? (http://www.deltasupplies.com/nsk3.htm)

Tebis
09-02-2006, 08:15 PM
So as I understand, most of the polishing is still done by hand.

Does anyone use a Luster like this? (http://www.deltasupplies.com/nsk3.htm)

yeah that's a profiler,i use it mostly for ribs.

bluechip69
09-07-2006, 02:11 PM
The profiler you show is mostly used with a stone. I have used these ,but like I said with a stone only. I use a felt strip and diamond polishing compound, much like whats on the site with the profiler, and use my hand.

Curtis.

Tebis
09-07-2006, 05:16 PM
The profiler you show is mostly used with a stone. I have used these ,but like I said with a stone only. I use a felt strip and diamond polishing compound, much like whats on the site with the profiler, and use my hand.

Curtis.

What i do after the felt tip and diamond compound is I take a kleenex tissue and apply some diamond compound on it and repolish the surface i just finished ,this will remove any swirl marks the felt left behind.

bluechip69
09-07-2006, 10:49 PM
Tebis, good point about the tissue. I forgot to mention that most anything else will leave scratches. So using a tissue is a must. Also for general cleaning of the mold anytime after just polishing as well.

Curtis.

steedspeed
09-13-2006, 06:36 AM
How about .001 stepover on the cutter and leave it running for a month! Just kidding!

mcliffwatts
09-13-2006, 11:02 AM
hi guys ,here in the uk we use wet n dry paper 400 grit down to 1200 grit (on alluminium) dipped in light oil ,always in appossing directions so as to polish out previous grit lines then brasso with tissue ,,mirror mirror ,on steel tools get some one else to it .

mcliffwatts
09-13-2006, 11:04 AM
has any one converted an old bridgeport series 1 tape reader to pc controlled

mcliffwatts
09-13-2006, 11:18 AM
oh i forgot ,,Saddle soap if you want a really high mirror finish on the tool face , it works as a fantastic release agent as well saves having to spray every forth shot , you guys should be able to get it ,comes in block form white in color(spelt your way) some acrylic fab shops use it for polishing the edges with a buffer wheel ,its as rare as rocking hores pooh over here

cerberes
10-18-2006, 02:30 AM
If you looking for an additional method. I came across some polishing media called Cratex. I bought a kit from mcmaster-carr. You use the bits etc with a dremel and using the 4 different grits can get a beautiful polish. I followed up with the standard polishing compound and fluffy wheel.

Ron

barthmv
11-28-2006, 09:10 PM
Guesswin has a large selection of polishing supplies. I usually start with 320 grit then move to 400, 600, 1200 and then finish with semi-chrome polish. Molds have a mirror finish. I also high speed mill at 50,000 rpm with a .00002 scallop. Finish right out of the machine is almost perfect.

Wiseco
11-28-2006, 09:16 PM
:eek: Are you serious with the 0.00002 Step-over High speed mil??? If so, it must be a very small mold!

barthmv
11-29-2006, 05:04 PM
I had meant to say a .00002 scallop height not step over. I edited my message to state this but guess you didn't see the edit. We use a scallop height like this quite often. It elliminates much of the hand polishing and lets us retain critical dimensions.

barthmv

Zaki
11-30-2006, 01:29 AM
HI Guys
there are several ways to polish the mold, including the mirror finish machining. But mostly hand polish is require after mirror finish machining. The best ever process I found in my 22 years experiance of mold making is to use abrasive powder or paste with soft wood stick, liquid perrafin and/or coconut oil is extremely suitable as lubricant in this process. u can use it with hand or with reciprocating polisher/ lapper. stone polishing is also good, but some times stones distroy the precision profiles if its using carelessly. Normally we start with 150~350 grit, depends upon the roughness of mold and finish it with 1200~2000 grit depends upon the required finish. We also use diamond paste for some very high quality finish molds, normally with the high hardened molds. its saves time but price gone high.

psfairport
12-03-2006, 05:22 PM
I make auluminum molds for rubber compression molding and don't have to worry much about polishing. When I needed one polished I went to a jeweler buddy and gave me a quick lesson. Pretty much the same as what was mentioned earlier.

cadcam
04-29-2007, 06:40 PM
How about .001 stepover on the cutter and leave it running for a month! Just kidding! Actully .001 to .003 in mold making is a normal less polishing at the end.As I have done this for going on 20 years this way. the machines runs Lights out and some times for a few days. then less bench work.

Mold maker back round . Wax investemt, Palstic Injection and Die cast beside others.