Die Lube Spray Problems

8/8/2019 Die Lube Spray Problems

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cuea lookat the most significantchallenges eportedstampers ndhowsprayGanovercomehem,

DAVEMIELKE

ft l onstanLly anling expensive own-I time and retooline? roubled withVthe mess and safJty ssues f toomuch mis t ing? s ove r- r unde r ub r i -cation costing you time and money?You're not alone. According to a 2005research study conducted by AugustResearch, hese are some of the mostcommonly cited dielubrication chal-Ienges acing he stamping ndustry.

The top five dieJube problems, data

show, are:. Excessivemisting. Over-application of lubricant. Inadequate coverage of the work-

piece

Daye Mielke is a marketing and techni-cal specialist with Spraying Systems o.,Wheaton, L; tel. 630/665-5000, -mailmielkedl@spray. om.

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. Inability to corectly place ubricant

. Excessive ool wear.Of those responding to the suruey, all

actively involved in their company'sstamping operations, 30 percent usedstock less han 2 in. wide, 30 percentused stock 2 to 4 in. wide and40 percent used stock more than 4 tn.wide. Application methods, with morethan one method employed in manyshops, were reported as ollows: 75 per-

cent employed spraying, 33 percentused rollers, 25 percent used both spray-ing and ollers.20 ercent pplied ubri-cant by hand and a minimal percentageused a drip or similar method.

Optimize Spray CapabilityThe majorityof metalforming hops

use spray o apply ubdcant. The '?e ofspray ystem nd setup employed oes

a ong way toward whether ubricationworks effectively, Use the wrong sprayapplication and you most likely willbattle all five of the challenges istedabove. But proper setup will signifi-cantly reduce misting, minimize toolwear and ube use, and place ubricationjust where t is needed.

Spray meLhods ange from basic.economical airless setups o advancedatomizing systems. The more advanced

the system, he more control stampershave n achieving and maintaidng opti-mal lubrication. Here's how spray sys-tems can combat lubrication challenges.

Excessive MistingA common misconception of exces-

sive misting: little to no way to controlit. In reality, excessive misting has manycauses nd all ofthem are controllable.

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l nco r rec t oPe ra l ng Pre \ su re sExcessive ressure auses ver nistll-lg'eene rd l ly. o r ' t yd r r t r l i c p t a1 or ' r i r -

atolnizing systeIns, he higher the pres-

sure thc greater he amount of atol-n-

i za t ion . As a ru l e ' keePpressure o a minit-num.Incorrect sPraY trP-

Using he ncorrect iP or aDapp l i ca t ion causes exccssnristing. Fo r instance, 95cleg. prav iP wili cover 8in.-rvidestock rom a distanceof about 3.5 n. from the worksu r ace , abou t the recom-mended maximru.n sPraYingdistance. or ha t lP to coverstock 12 l5 in. $'ide, t nrust

be moved to 5.5-7 n. abovethe su r f acc , r e su l t i ng inextremciy high nisting, oversplay and uirdc'raPPlicationln.rportant: (eeP sPraY is -tances o a minimum. Morenrist der.elops as th e ti Plocates artl.rer awaY iom thestock, ultimatelv escaPilrg osuLr-ounclingreas. hange oir vicler ngle Prav iP or addaclclitionrl 'rozzles o mini-niize spra,v eiglrt.

Incorrect flow ratesLubricants differ in viscosi-ties.A tip or nozzle hat worksrveli fo r a heavier viscositycauses xcessive isting \'henspraying ower viscositYubri-cants. Match th e lo\\ 'rate otth c nozzles r tiPS with theJubricant o tre sPraYed. ike-wise,when "-or in g with airatornizing s1-stcms, ir andlicluidpressures us t change

as viscositv hanges.he same

is tlue lvtth sPriqr etuPs rnozzles. prav -tozzle uPPli-er s cirnhelp here.

Unstable ambient condi-tions-Excessive ai 1 nlovenent fron blowels or fanscan carry spraY arther hanthe intended talget. Rernovethe source or Provide ade-quatc solation, such as enclo

sures, or the spray area. Though son-re

l i l - e . c \Pe l l5 ivend d ; f l i .L r l to rna n

tain, al enclosed system allows tb e

stamper o recycle xcessubricant an d

eliminate overspr;11

Spray-Tip Selection

Correct lncorrect

Th e correct spriry ip s and nozzlesplovide for improved n.rist ontrol, but

selection an be difficult.Choose n lutomatic nozzle vith;l

positive hut-offatthe PIa)'tip o elim-inate excess Pray nd associ

ated nlist. Autorlatic nozzlesalso al1ow or raPid esPonse,drip reduction or elirnination,and improvcd overall systelncontrol. l-re es t nozzles ndspra.v jPs offer irigh transterefficiencl', where a argcr Per-centage of sP l rY Pirrticlestransfer directlY rot'n he noz-zl e o the argeted bject

Another optioll: Lo w vol-ume lorv pressure LVLP)airatonizing setrlPs, hich rvorkn'ell for low viscosity lutrricants an d produce ittle mist.Bu t th e higher th e lube vis-cosity he higher the Pressulean d capacit,v eeded o accu-ra t e ly p roduce he PIoPerspriy Pattern an d Perrornance . FoI h ghc r-v i scos i YIubr i can t s , a h igh vo lumelow pressure IVLPsetup maybe a bettet- nswer. ransferefficiency of botl.r LVLP and

HVLP general\ ' anges iortt30 o ti 5 percent.

Ne$'er to spla.v sYstems'h i g h t r a n s f e r e f f i c i e n c l '(HTE) air'-atomiztng etuPsare designed o Pr.ovide aximum trirnst-er ron.t he noz-zle to th e work surfirce atoperating pressures s ow as 5psi. Test data sllo\\' hat transfe r efticiency as high as 85perc..nt witlt a lubricant vis-cosity of 76 centiPoise. TE

nozzles llow or it'tcI ases nddec reases n Pres su re s omatch lh e lubricant rvhileLVLPand HVLP setuPs matntain specific Peratlng anges.

Electlostatic P1 )'s)'stens'also ne w enploy a PositivelYcha rged pray droP le t ha talmost mn]ediatelY ttractsto the stocli's gt-ounded sur

When otating spray ip initiallyselected or wider stock

tt"ii), io cou"r n'arrowei tock30 to 70 percent more ubricantis aoDlied ha n needed right).Select pray ips to cover'soecilic

stock width using a minimal spray eight'

Using MutiPleNozzles

ProPer SPraY OverlaP

Wider tock ma y equire multiple nozzles Us emultiple nozzlei, op an d bottom, on stock wider ha n 6 in 'an d check he tip's pray pattern. A common lat-spray ipmust overlap he adiacent attern by 20 to 30 percent o pro-

vide proper overage.

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Change Tips to Avoid Heavy Genter Distribution

ldeally, spray ip will disttibute ubricant n a flat pyramid hape with a bit more n lhe center section elow he tip 0eftillustration). orn splay ips commonly av e a heavy entel distribution, ith less distribution o th e pattern edges right).

face. The result: a 40- to go-percenttransfer of liquid to the surface. Butnot all lubricants can be sufficientlycharged o achieve he higher transferrate,which s why he percentage ariesso greatly. Water-based ubricants chargemore easiJy nd more apidly han heirpetroleum-based in .

The electrically charged spray maybecome a concern when used n directcontact with floor personnel. Anotherconsideration: An electrostatic systemcan cost hree to six times more than a

conventional configuration. Electrosta-tic spray, still in deyelopment, o-dlatecan onll address oil or 5heet nteringthe stamping press. t can't be used orin-die application.

Over-Application f LubricantOver-application often results rom

choo" ing 5pray ip wi thou t p rope r lyconsidering ubrication needs. Pay care-ful attention to nozzle capacities, prayangles and spray distances, nd matchthem to the type ofstock, the ubricant

and the amount ofcoverage desired. Aspra) ip that worftswell or heavier-vis-cosity lubricants results n over-appli-ca t ion y nea r ly 0 pe rcen t hen usedwith a ighter-viscosity material. Over-application also can occur following achange o a slower eed ate while con-tinuing o use higher-feed ale nozzle.

A common, but poor, practice s torotate spray ips instead of selecting a tip

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Clogged or damaged ips result in animproper spray pattern with streaks ormissing pray, s shown here. Replaceworn, clogged or damaged ips andinspect ip strainers nd check valves.

with a narrower spray pattern. Whenrotating a spray ip initially selected orwider stock, to coyer narrower stock,30 to 70 percent more lubricant rsapplied han needed. Select pray ips tocover a specific stock width using aminimal spray height.

Worn spray tips also cause over-application, A worn or damaged spray-tip orifice results n a higher flow rate,leading o excessive pray. mproper tipmainlenance s a major cause forificedamage. Do not clean or unclog spraytips using mproper tools, such as metalprobes or screwdrivers. Use a cleaning

tool made of softermaterial, such as atoothbrush or toothpick.

Fo r bener control ofercessive ubri-cation, choose he right tip or nozzle orthe lubricant being applied and implement a nozzle-maintenance plan.Replace worn or damaged spray tipson a regular basis o maintain systemintegrity, control waste and reduce costs.

Inadequate overageof the Workpiece

As with over-application, nadequate

coverage esults rom incorrect tip ornozzle selection. Be certain that thespray tip or nozzle covers the stockfrom edge to edge. Wider stock mayrequire multiple nozzles-use multiple nozzles, op and bottom, on stockwider than 6 in. And check the tip'sspray pattern-some spray tips mustoverlap he adjacent pattern by 20 to 30percent o provide proper coverage.

Other causes f inadequate overageinclude intermittent-spray or squirt-type systems hat can result n hear,y rthin spots, pray nozzles ositioned oofar from the lubrication target, andclogged or damaged spray nozzles.

1o help ombat nadequate overage,employ regular system maintenance.Worn spray ips commonly have a hearycenter distribution, with less distribu-tion to the pattern edges. Clogged ordamaged ips cause an improper spraypattem with streaks or missing spray.

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Replace worn, clogged or damaged ips

un d inrp".t tiP strainers an d checkyalves. Also helpful: Pressurized pray

systems, which offer more-consistent,even coveraSe.

A good option for imProved cover-

ag eontrol s a turnkey' ullyautomal-

ed system hat monitors flow and sys-

tem oPeration electronically. Most of

these systems employ automatic (air- or

electrically-driven) nozzls, manifoldsand controllers.

Inability to CorrectlYPlace Lubricant

Getting lubricant to iust the right

spot ca n be difficult n some applica

tions, especially deep draws. Deep draw-

ing requires plenty of lubricant, at the

right time and n the correct area. Flex-ible magnetic-mount feed ubes Placedon the sides of the die can help. When

the die opens, nozzles at the end ofthe

tubes spray the lubricant on required

areas. For longer spray distances' con-

sider narrow-angle or solid-stream oz-

zles. Or stampers may opt for recipro-cating arms-linear or robotic-thatenter and spray he die completely when

it opens.A solution can be as simPle as

adding nozzles for extra-wide stock'

When reverting back to narrower stock,simply place a Plug in the unwantednozzles.

Excessive oolWearThe reaction of metal-to-metal con-

tact causes ear, no matter the amount

of lubrication applied. However, with

correct ubricants nd ubricationmeth-

ods, stampers can minimize tool wear.Continued, proper lubrication with

consistent and even coverage of the

stock at the point where it feeds nto thepress s the best way to control wear.bften, stampers coat only one side of

the stock, even though friction and

binding occur on both. Coat both sides.Ifproblem spots equire extra ubrr-

cation, use side-mounted nozzles to

spray he die. Another option: Substi-tute a full-cone nozzle or the standardflat-spray nozzle. Full-cone nozzlesdeliver a much heavier coating than

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their flat-spray counterparts. Also,

solid-strearn nozzles can provide cov-

erage of a targeted sPot.Proper nozzle an d tiP selection'

s e lup and main tenance o much in

combating tool wear and successfullymeeting other lube challenges. mple-

ment a regularly scheduled nozzle-maintenance Plan o keep he lube sys-

tem operating at peak efficiency, and

tap the exPertise of lubricant and sys-

tem suppliers. A reputable supplier has

experts available or consultation and

can offer a range ofProducts and serv-

ices uc h as esting' nalysis nd abri-

ca t ion o ensu re he igh t ub r i ca t ion

solution. Thy can answer any ques-

tions regarding proper nozzle selec-

tion, application and mist elimination,and should be willing to come onsite to

assess he stamper's ube-delivery needs

and current system. MF

Switch rcm inefficient and costly spray, drip canand hand ubrication methods to Progrcmmable

ttJni-ROLLER'sand start saving mmediately!

Fota No Ohligation valuation,skaboul

Un'-R0IER/SPR0LLERystem ontigurcd1ry'ur

coiland latstock pplications.CalloltFrce: $ f,anada800) 53'5462

UNIST, nc. 4T34 36th Street SE Grand Rapjds' Ml 49512 USA

Phone: 616) 94 9 0853 Fax:(616)94e-e503e mail i unimail@Linistom www unlst co m

I 'IICFO.TLUI'IZATTO'T PEO'U(TS FO R NUSTRY

write no . 19 DECEMBERO O 5 3 3

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Die Lube Spray Problems