PLASMA ARC CUTTING WITH LASER CUTTING QUALITY TIPS AND TRICK

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Berkat diskusi singkat dengan rekanan dari workshop laser cutting yang membuat statement bahwa potongan plasma cutting tidak akan bisa menghasilkan potongan dengan bidang potong yang lurus dan sudut yang sempurna , saya menjadi termotivasi untuk mencari cara bagaimana untuk menghasilkan potongan dengan cut edge yang tanpa kemiringan pada sisi potongnya (bevel angle)

Memang plasma cutting memiliki kekurangan dibandingkan dengan laser cutting, namun kelemahan tersebut dapat diatasi, diminimalkan bahkan di hilangkan dengan beberapa metode.

• Fine tuning plasma arc cutting parameter

Mengacu pada troubleshooting manual dari hypertherm saya membuat metode melakukan fine tuning dengan membuat table plasma cutting trouble shooting. Dimana dalam table tersebut harus ada semua parameter potong plasma.

Kemudian dilanjutkan dengan pembuatan sample benda potong yang menggunakan parameter yang ada pada manual book mesin hypertherm powermax 1650.

Dari sample yang dihasilkan saya menentukan satu parameter yang akan dirubah, perubahan harus di control dengan resolusi yang konstan (contoh: menggunakan resolusi 50 mm / menit untuk merubah kecepatan potong)

Setelah menemukan speed yang optimal saya melanjutkan ke setting ampere (menggunakan resolusi 5 amp untuk menaikan dan menurunkan setting ampere).

• Loop cutting

Setelah fine tuning parameter plasma arc cutting saya temukan saya tinggal membuat cnc code dengan menggunakan software FIGDEF 8 & KAP 80 profesional edition. Dalam program tersebut saya memodifikasi sudut sudut potong dengan menambahkan loop.

Dengan melakukan semua langkah di atas saya dapat menghasilkan benda potong dengan sisi potong yang lurus dan sudut yang sempurna :

PLASMA CUTTING STRAIGHT CUT EDGE NO BEVEL ANGLE - PERFECT CORNER 

NESTING PLATE WITH LOOP METHOD TO MAKE PERFECT CORNER CUTTING

EMPTY NESTING PLATE WITH LOOP CORNER

LOOP CORNER

Percobaan di atas dilakukan menggunakan :

1. PNC-10 elites, KOIKE ARONSON (CNC PORTABLE)
2. Powermax 1650, Hypertherm
3. 100 amp mechanized shielded torch
4. FIGURE DEFINITION 8, KOIKE
5. KAP 80, KOIKE

REFERENSI :

POWERMAX 1650 OPERATOR MANUAL - 804480r3

http://www.centricut.com

PLASMA CUTTING VS LASER CUTTING IN MY EXPERIENCE

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Seperti David vs Goliath, demikianlah saya merasa jika membandingkan kualitas benda hasil potong menggunakan plasma cutting dibanding dengan yang menggunakan laser cutting.

KEKURANGAN PLASMA CUTTING

Proses plasma cutting mempunyai banyak kekurangan bila dibandingkan dengan laser cutting dari sisi kualitas produk.

Kekuranganya bila dibandingkan dengan plasma cutting adalah :

1.       Hasil potong pada sudut tidak bisa menyudut sempurna selalu ada radius kecil pada bagian bawah benda potong.

2.       Sisi hasil potong selalu memiliki kemiringan - bevel angle cutting edge

3.       Tidak bisa membuat lubang yang lebih kecil dari 20mm.

PLASMA CUTTING (BEHIND) )VS LASER CUTTING

PLASMA CUTTING (BEHIND) )VS LASER CUTTING

PLASMA CUTTING memiliki segmen yang berbeda di industry metal sheet fabricator

Meskipun banyak kekurangan namun biaya investasi System Plasma cutting jauh lebih murah dibanding dengan laser cutting sehinga plasma cutting tetap memiliki pasar di segmen yang berbeda di industry sheet metal fabrication. Dan karena system plasma cutting yang lebih sederhana daripada laser cutting maka penerapan dan persiapan SDM lebih mudah dan lebih cepat di gunakan di line produksi.

NOTES :

Biaya investasi laser cutting system hardware + software kurang lebih 5 milyar rupiah

Biaya investasi plasma cutting system hardware + software kurang lebih 250 juta

PLASMA CUTTING SAMPLE : PLAT ASTM A36 

PLASMA CUTTING LEAD IN - LEAD OUT AND GOOD  TORCH  DIRECTION

PLASMA CUTTING NOT PERFECT CORNER

 Bacalah referensi : :http://www.teskolaser.com/laser_cutting2.html

Standard metal cutting processes: laser cutting vs. plasma cutting

Laser manufacturing activities currently include cutting, welding, heat treating, cladding, vapor deposition, engraving, scribing, trimming, annealing, and shock hardening. Laser manufacturing processes compete both technically and economically with conventional and nonconventional manufacturing processes such as mechanical and thermal machining, arc welding, electrochemical, and electric discharge machining (EDM), abrasive water jet cutting, plasma cutting, and flame cutting.

Plasma (arc) cutting was developed in the 1950s for cutting of metals that could not be flame cut, such as stainless steel, aluminum and copper. The plasma arc cutting process uses electrically conductive gas to transfer energy from an electrical power source through a plasma cutting torch to the material being cut. The plasma gases include argon, hydrogen, nitrogen and mixtures, plus air and oxygen.

Normally, a plasma arc cutting system has a power supply, an arc starting circuit, and a torch. The power source and arc starter circuit are connected to the cutting torch through leads and cables that supply proper gas flow, electrical current flow, and high frequency to the torch to start and maintain the process. The arc and the plasma stream are focused by a very narrow nozzle orifice

The temperature of the plasma arc melts the metal and pierces through the workpiece while the high velocity gas flow removes the molten material from the bottom of the cut, or the kerf. In addition to high energy radiation (Ultraviolet and visible) generated by plasma arc cutting, the intense heat of the arc creates substantial quantities of fumes and smoke from vaporizing metal in the kerf..

The table that follows contains a comparison of metal cutting using the CO₂ laser cutting process and plasma cutting process in industrial material processing.

Fundamental process differences

Method of imparting energy	Light 10.6 µm (far infrared range)	Gas transmitter
Source of energy	Gas laser	DC power supply
How energy is transmitted	Beam guided by mirrors (flying optics); fiber-transmission not feasible for CO2 laser	Electrically charged gas
How cut material is expelled	Gas jet, plus additional gas expels material	Gas jet
Distance between nozzle and material and maximum permissable tolerance	Approximately 0.2" ± 0.004", distance sensor, regulation and Z-axis necessary	0.010" to 0.02"
Physical machine set-up	Laser source always located inside machine	Working area, shop air and plasma torch
Range of table sizes	8' x 4' to 20' x 6.5'	8' x 4' to 20' x 6.5'
Typical beam output at the workpiece	1500 to 2600 Watts	Not applicable to this process

Typical process applications and uses

Typical process uses	Cutting, drilling, engraving, ablation, structuring, welding	Cutting
3D material cutting	Difficult due to rigid beam guidance and the regulation of distance	Not applicable to this process
Materials able to be cut by the process	All metals (excluding highly reflective metals), all plastics, glass, and wood can be cut	All metals can be cut
Material combinations	Materials with different melting points can barely be cut	Possible materials with different melting points
Sandwich structures with cavities	This is not possible with a CO2 laser	Not possible for this process
Cutting materials with liminted or impaired access	Rarely possible due to small distance and the large laser cutting head	Rarely possible due to small distance and the large torch head
Properties of the cut material which influence processing	Absorption characteristics of material at 10.6 µm	Material hardness is a key factor
Material thickness at which cutting or processing is economical	~0.12" to 0.4" depending on material	~0.12" to 0.4"
Common applications for this process	Cutting of flat sheet steel of medium thickness for sheet metal processing	Cutting of flat sheet and plate of greater thickness

Initial investment and average operating costs

Initial capital investment required	$300,000 with a 20 kW pump, and a 6.5' x 4' table	$120,000+
Parts that will wear out	Protective glass, gas nozzles, plus both dust and the particle filters	The cutting nozzles and electrodes
Average energy consumption of complete cutting system	Assume a 1500 Watt CO2laser: Electrical power use: 24-40 kW Laser gas (CO2, N2, He): 2-16 l/h Cutting gas (O2, N2): 500-2000 l/h	300 amp Plasma Electrical power use: 55kW

Precision of process

Minimum size of the cutting slit (kerf width)	0.006", depending on cutting speed	0.002"
Cut surface appearance	Cut surface will show a striated structure	Cut surface will show a striated structure
Degree of cut edges to completely parallel	Good; occasionally will demonstrate conical edges	Fair, will demonstrate non-parallel cut edges with some frequency
Processing tolerance	Approximately 0.002"	Approximately 0.02"
Degree of burring on the cut	Only partial burring occurs	Only partial burring occurs
Thermal stress of material	Deformation, tempering and structural changes may occur in the material	Deformation, tempering and structural changes may occur in the material
Forces acting on material in direction of gas or water jet during processing	Gas pressure poses problems with thin workpieces, distance cannot be maintained	Gas pressure poses problems with thin workpieces, distance cannot be maintained

Safety considerations and operating environment

Personal safety equipment requirements	Laser protection safety glasses are not absolutely necessary	Protective safety glasses
Production of smoke and dust during processing	Does occur; plastics and some metal alloys may produce toxic gases	Does occur; plastics and some metal alloys may produce toxic gases
Noise pollution and danger	Very low	Medium
Machine cleaning requirements due to process mess	Low clean up	Medium clean up
Cutting waste produced by the process	Cutting waste is mainly in the form of dust requiring vacuum extraction and filtering	Cutting waste is mainly in the form of dust requiring vacuum extraction and filtering

CORNER RELIEF METAL SHEET FABRICATION - WITH LASER CUTTING & CNC BENDING

jasa potong tekuk plat, laser cutting,bending, cnc press brake machine, surabaya, indonesia, Trunpf, amada, training drafter untuk industri fabrikasi plate baja
Pada tekukan plat yang difabrikasi dengan cara modern bisasanya terdapat lubang kecil pada sudut sudutnya, lubang kecil ini disebut Corner Relief.

Fungsi dari Corner Relief adalah untuk mencegah deformasi yang tidak di inginkan pada produk plat tekuk, biasanya produk corner relief dibuat dengan proses laser cutting atau blanking.

Berikut adalah contoh aplikasi metal sheet corner relief pada proses tekuk plat menggunakan CNC Press Brake Machine, perhatikan lubang lubang kecil pada sudut sudutnya

(klik untuk memperbesar gambar)

PRESS BRAKE CNC MACHINE

Macam macam bentuk corner relief  :

(klik untuk memperbesar gambar)

corner relief type

Contoh gambar aplikasi corner relief pada gambar produk metal sheet fabrication - digambar menggunakan Autodesk Inventor 2012:

(klik untuk memperbesar gambar)

Isometri drawing of Relief corner

unfold model. flat pattern of relief corner

contoh produk yang dihasilkan dari Laser cutting dan CNC press brake machine setelah di powder coating :

klik untuk memperbesar gambar

*Berdasarkan pengalaman pribadi ukuran minimal dari corner relief adalah 1,5 kali ketebalan plate. jadi kalau plate yang anda gunakan tebalnya 2mm maka ukuran corner reliefnya minimal diameter 3mm

MARI BELAJAR TEKNOLOGI LASER UNTUK POTONG PLAT BESI

Mari belajar teknologi potong laser A.K.A Laser cutting, keinginan belajar ini timbul dari pengalaman saya ketika mengerjakan proyek yang membutuhkan banyak pekerjaan laser cutting dan CNC bending. 

Namun pekerjaan yang saya berikan kepada perusahaan yang menerima jasa potong laser dan tekuk CNC sering kali mengecewakan dari sisi Kepresisian dan kehalusan potong. Setelah mempelajari dan berdiskusi dengan beberapa praktisi dan operator saya menemukan akar permasalahannya yaitu "SDM dan TAKUT "

SDM yang tidak memiliki passion yang bekerja hanya untuk mendapatkan gaji sangat cuek dengan hasil potongnya mereka tidak memiliki minat untuk belajar sehingga mereka bekerja hanya berdasarkan kebiasaan dan hafalan saja. "Pokoknya habis pencet tombol A - pencet tombol B" Tanpa mengerti esensi dari tindakan yang mereka lakukan, sehingga banyak parameter yang tidak mereka kontrol.

SDM yang takut cenderung berbohong dan tidak jujur sehingga akar permasalahan yang sebenarnya tidak pernah terungkap oleh pihak manajemen sehingga akan terjadi siklus pengulangan kesalahan yang ujung ujungnya mengecewakan costomer seperti saya.

Karena sering dikecewakan dengan produk laser cutting hasil dari perusahaan penerima jasa laser cutting, maka saya sebagai R&D diberi kewajiban oleh perusahaan tempat saya bekerja untuk mengaplikasikan plasma cutting Hypertherm Power Max 1650 + CNC PNC-10 buatan koike + software FIGDEF 8 dan KAP 80 

Akhirnya saya membentuk Tim plasma cutting yang saya training dan bentuk sistem operasionalnya sampai lancar.

Ternyata usaha saya tidak sia sia dan hasil potong menggunakan plasma cutting tidak kalah dengan laser cutting, namun tetap ada beberapa pekerjaan yang tidak bisa dikerjakan oleh plasma cutting yang saya misalnya membuat lubang lebih kecil dari 20mm dan Hasil potong pada sudut tidak sebaik jika menggunakan laser cutting namun hasil ini bisa diterima oleh QC karena masih dalam batas toleransi + -  0,3 mm

Tapi OK lah, sementara belum mampu beli mein laser kita pelajari dulu saja siapa tahu suatu saat nanti bisa di terapkan.

Laser Cutting

Precision sheet metal piercing Rapid profiling of sheet metal Clean and precise cut edges Intricate profiling of tube At Stevens Rowsell we operate a fully automated Trumpf 4kw Trulaser with two 8m tall material storage towers and an integrated sheet handling system for automated loading and unloading of sheets 3000 x 1500mm.  Benefits of using Laser cutting technology Our technologically advanced Trumpf Laser Machines provide us with an efficient, high speed and cost effective form of profiling sheet metal which ensures that the work we produce is competitively priced, is turned round quickly and has a superior clean cut and oxide free finish. The features and benefits to our customers are thus:- High speed cutting with Nitrogen - gives clean edges, no oxide and limited discolouration and therefore a more visually aesthetic finish Auto Height Sensing - No material marking Positioning and dimension accuracy of 0.05mm guaranteed Oil on Pierce - (Anti Splatter) for cleaner dross free cut Laser Cat Eye – Allows the use of pre-punched / formed blanks Parts can be marked for identification purposes Advanced Process Control (APC) - Guarantees process reliability in piercing and cutting by automatically determining the exact sheet position on the laser bed and thus regulating the distance between the cutting nozzle and the work piece. This helps to produce a better cutting result regardless of the sheets unevenness and also eliminates the need to manually reposition the sheet thus preventing scratches to the underside of the work piece. Latest generation software - Automatically nests different part profiles from different jobs on the same sheet which helps us to maximise sheet utilisation & reduce wasted material as well as cutting more than one specific job at the same time. This software coupled with the laser technology we employ helps us offer highly competitive pricing and a genuine value for money metal cutting option. Intelligent planning - the software also reports back to our business system helping keep our production scheduling accurate and our delivery dates on time. Versatility - The laser beam is effectively a multifunctional tool  which can cut through a wide variety of materials (including coated sheet), whether thick or thin. Part geometry (size & shape) can be simple or highly complex enabling the laser to cut an infinite range of shapes and forms. We can produce one off prototypes or provide a quick turn around on production quantities. Customised automation - We have a fully automated laser cell incorporating two 8m tall sheet metal storage towers with 50 individual storage stations and an automatic sheet changer. The system fully automates the loading and unloading operations transporting raw material sheet to the bed of the laser (by means of suction cups).  An unloading rake then transports the finished work pieces and scrap skeletons from the machine to the finished parts stack whilst a new sheet is conveyed to the bed of the laser to continue the cutting cycle. The loading device enables seamless and constant handling even when heavy sheets are involved, doing away with the need for men and cranes to perform the operation. Material loading, production and parts unloading therefore all take place simultaneously, eliminating downtime, increasing capacity and reducing delivery lead times. These CO2 gas lasers operate according to the "flying optics" principle, whereby the laser beam is moved over the working area whilst the work piece remains static. This allows high processing speeds and very high quality cutting to be achieved independent of material weight. Download clip 1 of laser in action Download clip 2 of laser in action Making light work of a precise cut through steel How is our laser beam produced? A turbine prepares the laser gas (a mixture of carbon dioxide, nitrogen and helium) at a specific ratio and delivers the mixture to a discharge tube at high speed and under pressure. Inside the discharge tube there are electrodes which stimulate the mixture between 2 mirrors (called a resonator) to produce a laser beam. The output mirror allows a certain percentage of the beam to leave the resonator. The beam is then focussed onto a convex lens in the flying optic. The resultant laser beam has an output range of up to 3kw and the ability to cut through a wide variety of materials including;  Stainless Steel – up to 15mm  Mild Steel – up to 20mm  Aluminium – up to 10mm  Brass – up to 5mm SOURCE : www.stevensrowsell.com/