Gravator laser din imprimantă 3D

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cornelTT

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Cum am o imprimantă ce stă pe bară am zis să-i găsesc o întrebuințare. Ideea nu-mi aparține și am dat peste acest link,

http://www.instructables.com/id/Convert-a-3D-PRINTER-to-LASER-ENGRAVER-Under-40/

în timp ce mă documentam despre gravatoarele laser. Găsisem un gravator laser, de 40 w cu CO2, ieftin la 3900 ron și dorind să aflu mai multe despre aceste echipamente, am dat de acel link.

Ideea e interesantă numai că scopul principal pentru care doresc un gravator (tăierea geamurilor din plexi) nu poate fi pusă în practică cu un laser albastru.
Din ce m-am documentat pe net am înțeles că laserele vizibile nu pot tăia materiale transparente, nu din cauza puterii ci din cauza lungimii de undă a fascicolului.

Dar cum nu-mi iese din cap ideea de a avea un gravator cu costuri minime (70 dolari laserul de 2,5 mW cu lumină albastră Laser 2,5 mW), cred că am să mă apuc de treabă :D ,

mai ales că am dat peste acest site:

https://www.youtube.com/watch?v=WsTp_aDWLCo

Deci o întrebuințare tot i-am găsit :x
 
Sa ai grija la ochi! Ar fi bine sa-i faci o cutie, chiar daca e cu totul opaca. Eventual iti iei niste ochelari seriosi si deschizi usa sa te uiti la progres. Cu laserul nu-i de gluma. Am cochetat si eu cu ideea insa m-am lasat pagubas pentru ca era prea mare cutia (eu vroiam pt un CNC).
Vezi ca firmeware-ul de la Repetier are si setare de laser-cutter in config. Asa ca iti salvezi setarile din EEPROM si doar reflash-uiesti firmeware-ul. Poti folosi extruderul sau patul incalzit pentru alimentarea diodei laser.
Daca ai intrebari pune cu incredere. Spor la constructie.

PS: din cate stiu 2.5mW e cam putin, doar zgarie hartia dupa cateva treceri. Cam la 400RON gasesti ceva la 4W cu tot cu raditor si cooler
 
Mersi Ferrocarril.


Salut Strofo,

ce bine că am pe cine întreba, eu sunt varză la partea asta

din ce am înțeles din tutorial, laserul se cuplează la ventilator, sau extrudor2 în cazul meu (RAMPS 1,4).

Și se folosește comanda de M106-on și M107-off, pentru pornire/oprire laser.
De ce zici că trebuie să rescriu firmware-ul?
Practic imprimanta știe G-codul și trebuie doar valoarea pentru pornire/oprire laser sau puterea laserului (M106xxx).

Va trebui să fac cumva o cutie cum zici tu pentru extragerea fumului din timpul gravării.

Referitor la putere am înțeles de pe net că laserul de 2,5 poate tăia balsa sau carton de 2 mm la 2 treceri parcă.


Oferta ce o am pentru laserul de 40W CO2 e foarte tentantă (3900 ron), mai ales că are tot ce trebuie.
Dar totuși să dau atâția bani doar pentru hobby, măcar dacă ar produce. Și mai e un inconvenient, am înțeles că laserele pe gaz trebuie folosite măcar 5 minute pe săptămână, altfel se strică stând.
Ori eu lucrez la nebuniile mele când prind niște timp liber.
 
Cu mare placere.

O dioda laser ar trebui sa aiba atat un ventilator cat si comanda diodei; altfel se incinge foarte tare. Da-mi un link cu ceea ce vrei sa cumperi. La RAMPS, extrudoarele si patul incalzit au sigurante iar circuitele sunt ingrosate ca sa suporte puterea. Ventilatorul nu! Daca folosesti ventilatorul, pune un releu pe laser si doar comanda pe ventilator (il poti cumpara de la orice magazin auto dar sa bagi si dioda).

Uite aici lista completa de GCode valabila cu firmeware-ul de pe imprimanta (banuiesc ca e I3 sau similara): http://reprap.org/wiki/G-code . M106 e Fan On, M107 e Fan Off (doar ventilatorul).

Eu nu am gasit in lista asta codurile pentru pornirea si oprirea extrudoarelor sau heat bed. In general controlul EXT si heat bed e realizat intern, comenzile fiind doar de setare temperatura. Exista in CNC mode insa trebuie sa arzi noua configuratie: M3 e Spindle on CW, M5 e Spindle off. Chiar nu e dificil sa suprascrii, te pot ajuta.

Pentru 2D eu am folosit InkScape.

Da, cutia e buna si sa extragi fumul. Insa ai grija la ochi, eu am avut un incident destul de neplacut cu unul (mult mai puternic de 2mW insa ne atunci suflu si in iaurt).

Nu stiu sa-ti raspund despre puterea laserului, chiar nu ma pricep. Ce am mai citit si eu pe forumuri: din cate am inteles sub 4W nu merge decat sa innegreasca hartia, in nici un caz sa tai cartonul. Dar eu nu am testat. Acum te gandesti si tu cat de mare e platforma de lucru la laserul de 3900ron fata de imprimanta ta de 20x20cm. Am vazut si facute din motoare de cdrom de 4x4cm; o mare bataie de joc.
 
Scuze insa abia acum am deschis si linkul cu tutorialul. Vezi ca laserul aluia a venit cu un circuit propriu (e un driver de motor DC de putere, se gasesc si cu radiator). Da, in cazul asta il poti pune direct pe ventilator.
 
Mersi Strofo,

da și al meu va fi cu totul. Nu înțelegeam de ce trebuie și driverul, dar din ce ai scris acum m-am luminat și eu.

uite la ce m-am oprit eu

Laser 2,5 mW

uite ce ma găsit pe un site: sursă site Caracteristici lasere

Laser Modules for Cutting/Engraving (CNC)
The ability of a small diode laser to cut or engrave depends on many factors but the basic principle is that the laser must transfer enough power to the target to reach the burning temperature. Important factors are:
Surface adsorption by target (matt black is best).
Thermal conductivity of the target - if the target conducts too well e.g. metal, the heat is dispersed rapidly. For a material to be engraved or cut he target must adsorb laser energy more rapidly than it loses it in order to heat up.
The amount of laser energy per unit area of the target (the laser needs to be focused to a small point on the target rather than a big spot).
The power of the laser.
Commercial Laser Engravers
Most ‘small’ commercial laser cutters and engravers use a CO2 laser, typically with a power of 20-40W (20,000- 40,000mW).
A 20W CO2 laser can typically cut 3mm plywood and 8mm acrylic easily at full power and will run at ~5-10% power (1-2W) to engrave wood, cut paper etc.
CO2 lasers are commonly used simply because they are the cheapest way to generate laser light at these power levels.
The power output of common semi-conductor lasers (laser diodes) is much lower and the cost of laser diodes increases above a couple of watts to the point where they are no longer economic to use compared to a CO2 laser.
It is however possible to use laser diodes to engrave wood, cut thin paper, balsa wood and pattern resist layers for PCB etching. Reducing the cutting/ engraving speed is often required.
Laser Diode Performance
Laser diodes are produced commercially to have lifetimes of thousands of hours at their rated power. Often experimenters will run these diodes at higher powers (e.g. +50%)
and still get lifetimes of at least tens and sometimes hundreds of hours. The exact results vary from diode to diode and depend on a stable driver and adequate cooling.
 
[glow=red]Blue Laser Diodes[/glow]
The most powerful low-cost diodes are 445-450nm Blue (1.6W - 4.5W), these are often run at +20-30% of the rated power in engraving/cutting applications.
Our laser modules are all built with laser diodes running at the manufacturers rated maximum current, we do not overdrive the diodes to increase the output.
 
2W 445nm (Blue) Laser Diode Performance
Multiple slow passes are needed for thicker materials.
1-2mm white acrylic                 Cuts acceptably at 120mm/minute with 2-3 passes. / Engraves well.
1-2mm tinted acrylic                Cuts acceptably at 120mm/minute with 2-3 passes. / Engraves well.
0.125mm Mylar sheet              Cut/engrave
Paper, white, brown                 Cut/engrave
0.4mm hard card                     Cut at 100-150mm/minute /Engraves well.
3mm corrugated card              Cut/engrave
Balsa wood:                            Engraves well.
1/32″ Balsa:  Cuts well at 250-300mm/minute with one pass.  Two passes recommended for cleanest cut.
1/16″ Balsa:  Cuts well at 200mm/minute with two passes.
1/8″ Balsa:    Cuts acceptably at 150mm/minute with three passes.                 
2mm light plywood                  Cuts acceptably at 100-150mm/minute with three-four passes. / Engraves well.
0.5mm standard plywood        Cuts acceptably at 100-150mm/minute with three-four passes. / Engraves well.
2mm leather                            Cuts acceptably at 100-150mm/minute with three-four passes. / Engraves well.
5mm Foam board                   Cuts well at 150mm/minute with two passes.
Anodised aluminium               Engrave anodised finish only.
Bare metal (brass, copper, aluminium)  – no engraving or cutting possible.
Glass – no engraving or cutting possible.
          Typical Modules:
OFL419 2W 450nm Blue TTL Laser Module with Adjustable Focus 12V
OFL365 2W 450nm Blue Focusing Laser Module (12V) TTL Driver
OFL365-2 2W 450nm Blue Focusing Laser Module (12V) Analogue Driver
   
3.5W and 4W 445nm (Blue) Laser Diode Performance
The tests we have done with a 3.5W diode allow faster cutting / less passes but do not give a significant increase in the thickness of materials that can be processed.
Materials that require 2 passes with a 2W laser typically require 1 pass with a 3.5W or 4W laser. The higher cutting rate of the most powerful diodes normally gives a cleaner cut.
Typical Modules:
OFL419-2  3.5W 450nm Blue TTL Laser Module, Adjustable Focus 12V (CNC Engraving)
OFL365-1 4W 450nm Blue TTL Laser Module, Adjustable Focus 12V (CNC Engraving)
 
Red Laser Diodes
These are the cheapest laser diodes for powers of 200-300mW, a 700mW diode is available but is nearing the cost of the more powerful blue diodes.
200- 300mW red lasers are less well adsorbed than blue diodes so often paper and plastic need masking with a black marker or thin black paper to cut. They may also need several passes to cut materials.
250mW Red Laser Diode
Paper black                             Cut
Chocolate                                Cut/engrave
Paper white                             Cut with masking/engrave
Coloured fabric: silk, cotton     Cut
Hard Cardboard                       Engrave
Balsa, Plywood                        Engrave
 
Bluray (405nm) Laser Diodes
These diodes are available as in 100mW, 200mW and 500mW.
OEM versions of these diodes are normally extracted from high speed Bluray writers as these are much cheaper than catalogue components.
The 405nm laser light is adsorbed better than red laser light by many materials so black masking is not required.
200mW 405nm Laser Diode
Paper black                             Cut
Chocolate                                Cut/engrave
Paper white                             Cut /engrave
Coloured fabric: silk, cotton     Cut
Hard Cardboard                       Engrave
Balsa, Plywood                        Engrave
0.5mm balsa                            Cut/Engrave
500mW 405nm Laser Diode
Paper black                             Cut
Chocolate                                Cut/engrave
Paper white                             Cut /engrave
Coloured fabric: silk, cotton     Cut/engrave
Hard Cardboard                       Cut/Engrave
Balsa, Plywood                        Engrave
1.0mm balsa                            Cut
 
Building Laser Modules
To build a laser module 4 main items are needed:
Laser Diode (this is normally chosen by wavelength (colour) and power output)
Housing (this should be chosen to match the diode size, normally 3.8mm, 5.6mm or 9.0mm
and the expected heat dissipation requirements, most diodes can run at up to 60 degrees C)
Lens (this should be chosen to match the wavelength of the laser diode)
Driver (this should be chosen to match the current and voltage requirements of the diode, some drivers also have optional TTL switching for fast pulse operation)
Building a module will require the laser driver current to be set to match the diode, this is normally done using a dummy load such as:
OFL70 Component Bundle for 3A /5W Laser Diode Test Load (supplied with instructions)
Driver (this should be chosen to match the current and voltage requirements of the diode, some drivers also have optional TTL switching for fast pulse operation)
Analogue vs TTL Drivers
The difference between analogue and TTL drivers is as follows:
With a "TTL”  driver a TTL level signal (nominally 5V but normally anything between 2.5v and 5V will work) will switch the laser on or off.
The TTL circuit avoids the soft start function of the driver and allows rapid switching so a pulse width modulated (PWM) signal can be used to control the average power.
The switching is between off and full power, the power variation is from the pulse duration, e.g. a 50% pulse cycle will keep the laser on for 50% of the time so the average power will be 50%.
TTL drivers accept very rapid switching (thousands of times per second),
if the switching rate is greater than ~150Hz (times per second) the beam appears continuous to the eye but lower intensity (depending on the pulse width).
With an “analogue" driver the switching is the same except the laser output also depends on the voltage of the signal.
If a 5V signal is used the driver will act like a “TTL” module switching between 0 and 100% power with the pulse signal.
If the signal is less than 5V, e.g. 2.5V the laser will switch between off and 50% output.
Analogue drivers allow the true power to be varied by voltage and the the average power by pulse width.
 
Treaba cu dioda recuperata din DVD a facut-o un amic insa nu taia hartia, doar grava. In plus vezi ca in link se scrie clar ca majoritatea le folosesc cu +20% fata de puterea inscrisa pe ele, deci vreo 250mW in cazul tau. Insa eu nu as mari la atat pentru ca nu are radiator. Oricum pe driverul ala extern ai un potentiometru din care poti regla puterea de la iesire.
Ca sa taie bine va trebui sa ii faci focusul corect insa la imprimanta poti regla f fin axa Z. In plus ai si o lentila din care sa o reglezi.
Spor la mesterit! Sa ne tii la curent. Apropo, vei da jos extruderul sau ii printezi o prindere in paralel?