What should consider when choosing. using & maintaining ring die
What should consider when choosing、using、maintaining ring die?
With the growth of National economy and the living level of people, the demand of different kinds
of feed is improving, so it is with the demand of the main wearing part------the ring die, which
its quality directly affect the production cost and the feed pellet quality.
According to incomplete statistics, Ring wearing cost takes more than 30% of the total production
plant maintenance costs,and the feed pellet quality has tremendous impact on sales.Clearly,it
means a lot for feed producer to learn how to choose the right ring die.
The ring die is a wearing part with multi holes, densely covered die holes, high precision assembly
dimensions. and the wall of which is thin. When working, the feed is compressed by the rotating
extrusion ring die and the pressure roller, coming out from the inner wall outwardly through Die
hole into the strand, and then be cut to the desired length by the cutter particles. Then we make
some analysis about ring die selection, use and maintenance for your reference.
1、Selection of ring die
Ring die is generally made of carbon steel or alloy structural steel, or stainless steel by forging, machining, jig hole and heat treatment step system to do.
So far, the price of ring die sometimes high sometimes low, the main reason is the difference of material picking, process choosing and control. Some small factories producing domestic ring mold mainly composed of carbon or alloy steel by forging, die twist drill hole, and then processed by ordinary heat treatment together.Thus,this kind of ring die may emerge some problems,such as long-time process,high energy consumption, low production,bad quality of pellet. Another problem is low service life. A survey shows, the feed which produced by these ring dies have high iron content, which greatly affects the feed formula, the result mainly caused by poor wear resistance.
With the continuous development of market economy, China joining the WTO, only cheap feed got competitiveness on the market. For feed producers to reduce production costs and improve the quality of feed pellets is urgently needed, and these qualities are largely determined by the level of quality ring die.
According to ring die working conditions, feed producers should use those advanced production plant who can have reasonable selection and reasonable process in producing ring die.
You’d better use stainless steel ring die, ring die made of stainless steel forging stock, is the essence of high quality ring mold life assurance;
The die hole should use gun drilling process, the use of multi-position rifle drill holes ensure the smooth bore die without forming a crooked hole,so to achieve faster, better quality particles (particle surface is smooth, uniform, small powder rate, etc.).
Should choose the ring die who got by vacuum heat treatment, vacuum heat treatment of the ring mold is a further guarantee of the quality of the previous step process, which guarantees high wear resistance, high strength, and the smoothness of the orifice ring mold materials were effective protection (to avoid the oxidation of the die hole).
二、環(huán)模的使用
首先，在選用優(yōu)質(zhì)環(huán)模的前提下，應(yīng)根據(jù)生產(chǎn)飼料品種、配方及產(chǎn)量選用合適的�？仔问�、開孔率及壓縮比（壓縮比=�？椎挠行чL度/模孔直徑）。一般來說，直形孔和階梯形孔適于加工配合飼料；外錐形孔適合加工脫脂糠等高纖維的飼料；內(nèi)錐形孔宜加工草粉料類比重輕的飼料。在保證環(huán)模強(qiáng)度的前提下，盡量提高環(huán)模的開孔率，對于有些品種的飼料，在保證合理壓縮比的條件下，環(huán)模過于壁薄，以致環(huán)模強(qiáng)度不夠，生產(chǎn)中會(huì)出現(xiàn)爆模現(xiàn)象，此時(shí)應(yīng)當(dāng)在保證模孔有效長度的前提下，增加環(huán)模的厚度和增開減壓孔。通常來說，含谷物高的配合飼料宜選之間的壓縮比；熱敏感飼料及尿素飼料宜選用5-8之間的壓縮比；含天然蛋白質(zhì)高的濃縮飼料適于選用5-11之間的壓縮比；奶牛配合飼料適宜選用7~15之間的壓縮比。另外還可以在考慮飼料基本配方后，依據(jù)生產(chǎn)者自己要求的飼料品質(zhì)調(diào)整具體的壓縮比，比如選用稍低的壓縮比對于增加產(chǎn)量、降低能耗、減輕環(huán)模的磨損等有利，但是這樣一來將會(huì)降低飼料的品質(zhì)，如顆粒不夠結(jié)實(shí)，外觀松散長短不一，飼料的粉化率高，反之，則對顆粒品質(zhì)有利（顆粒外觀光滑而有光澤，粉化率小），但會(huì)增加產(chǎn)品的生產(chǎn)成本。
其次，環(huán)模與壓輥之間工作間隙合理與否對環(huán)模的有效使用具有重要影響。一般來說，環(huán)模與壓輥之間的間隙為0.1-0.3之間，以實(shí)踐經(jīng)驗(yàn)來說，用手扳動(dòng)環(huán)模旋轉(zhuǎn)的同時(shí)，壓輥達(dá)到似轉(zhuǎn)非轉(zhuǎn)的狀態(tài)為佳。那么，如何調(diào)整環(huán)模與壓輥之間的間隙呢？通過我們的實(shí)踐經(jīng)驗(yàn)得知，當(dāng)新模裝機(jī)后，首先，松動(dòng)壓輥調(diào)節(jié)螺栓將壓輥調(diào)整到壓輥外圓面緊靠環(huán)模內(nèi)圓面的狀態(tài)；其次，依次調(diào)整壓輥偏心軸使各壓輥與環(huán)模之間間隙適當(dāng)，預(yù)緊調(diào)節(jié)螺栓，扳動(dòng)環(huán)模，逐步調(diào)節(jié)間隙，使壓輥達(dá)到似轉(zhuǎn)非轉(zhuǎn)的工作狀態(tài)，最后緊固調(diào)節(jié)螺栓。當(dāng)新模裝機(jī)時(shí)，通常要求環(huán)模與壓輥之間間隙比您所需要的稍大，這有利于新環(huán)模與舊輥之間的平穩(wěn)過渡，等新模與舊輥完成一定的磨合期以后，可以將間隙調(diào)整到您所需要的間隙。在使用中，都是保環(huán)模而犧牲壓輥，因?yàn)榄h(huán)模的價(jià)格是壓輥價(jià)格的十幾倍甚至幾十倍，所以在使用中，在選用合理間隙的情況下，壓輥的硬度不能太高，也就是說，壓輥的耐磨性不能比環(huán)模的耐磨性高。
環(huán)模在生產(chǎn)過程中，對所使用的物料要求進(jìn)行必要清理，避免物料混有大塊砂石、砂粒、鐵塊、螺栓及鐵屑等硬顆粒。因?yàn)檫@些夾雜加速了環(huán)模的磨損，而且大量的、大硬夾雜將造成環(huán)模多次受力，使環(huán)模產(chǎn)生疲勞，當(dāng)某次受力超過環(huán)模的強(qiáng)度極限時(shí)，環(huán)模將出現(xiàn)爆�，F(xiàn)象。
最后，操作者在新裝或更換環(huán)模時(shí)，對于通過錐面裝配的環(huán)模來說，新裝模時(shí)，要求避免造成錐面的碰傷及刮傷，并對其錐面及其配合傳動(dòng)輪緣錐面進(jìn)行必要清理，涂油裝配。更換環(huán)模時(shí)，拆卸，不碰傷及刮傷錐面，涂油保護(hù)。對于經(jīng)常需更換環(huán)模的顆粒機(jī)來說，要求定期對傳動(dòng)輪緣進(jìn)行檢查，防止其過度磨損而導(dǎo)致模具定心銷的斷裂，因?yàn)檫^度的磨損將會(huì)影響環(huán)模與輪緣之間的配合，配合不緊，當(dāng)環(huán)模工作時(shí)將對模具定心銷產(chǎn)生剪切力而導(dǎo)致斷裂，當(dāng)產(chǎn)生這種情況后，千萬不要誤認(rèn)為是銷的強(qiáng)度不夠而換成高強(qiáng)度的銷，最終只能導(dǎo)致環(huán)模損壞和安全銷經(jīng)常性的斷裂。因此，對環(huán)模的配合錐面及配合的傳動(dòng)輪緣的錐面進(jìn)行保護(hù)和定期的檢查是相當(dāng)必要的。對于抱箍式裝配的環(huán)模來說，對其裝配面及其配合的元件的保護(hù)與檢查也是相當(dāng)必要的。當(dāng)壓輥使用一段時(shí)間后，會(huì)出現(xiàn)磨損現(xiàn)象，影響了與環(huán)模的配合精度，從而影響了環(huán)模的生產(chǎn)產(chǎn)量，應(yīng)對其進(jìn)行必要的修理或更換新的環(huán)模。
三、環(huán)模的基本維護(hù)
俗話說，磨刀不誤砍柴工。對環(huán)模進(jìn)行合理的維護(hù)保養(yǎng)是環(huán)模經(jīng)濟(jì)、有效使用的一部分。
在生產(chǎn)過程中，操作者經(jīng)常發(fā)現(xiàn)，環(huán)模在使用過程中，通常會(huì)出現(xiàn)堵塞、磨損、封口及內(nèi) 翻等現(xiàn)象，這時(shí)，如果不對其進(jìn)行必要維護(hù)，將造成產(chǎn)量降低，能耗增加，甚至不出料等現(xiàn)象。此時(shí)，對環(huán)模進(jìn)行基本維護(hù)的方法是，先將環(huán)模工作內(nèi)圓面進(jìn)行磨平，然后進(jìn)行倒角。
當(dāng)更換環(huán)模時(shí)，要求趁熱模將含油物料充填模孔，以便下次生產(chǎn)時(shí)使環(huán)模達(dá)到最佳狀態(tài)。
綜上所述，只有對環(huán)模進(jìn)行正確選用、合理使用和有效的維護(hù)，才能降低成本，提高效率，創(chuàng)造顆粒品質(zhì)，增強(qiáng)產(chǎn)品市場競爭力，迎接挑戰(zhàn)，為企業(yè)創(chuàng)造更多的經(jīng)濟(jì)效益。